GMAT prep Questions (Correct Answers)
What are the first ten prime numbers?Correct Answers2, 3,5, 7, 11, 13, 17, 19, 23, 29
Sum of two primesCorrect AnswersAll prime numbers are odd, except the number 2.
Thus, the sum of any two primes will be even unless one of those primes is the number
2
If a sum of primes is odd, one of those primes must be the number 2
Counting total factorsCorrect AnswersIf a number has prime factorization a^w x b^y x
c^z (where a, b, and c are all prime), then the number has (w +1)(y + 1)(z + 1) different
factors
Perfect squaresCorrect Answers1) All perfect squares have an odd number of total
factors, which always sum up to an odd number
2) Prime factorization of a perfect square contains only even powers of primes
Should vs. MustCorrect AnswersMust = binding obligation
Should = moral obligation
Relative pronoun rulesCorrect AnswersThat - if the clause is essential, it must begin
with "that" rather than "which"
Who/whom - must modify people
Which - cannot modify people
Whose - can modify people or things
Which/whom - sometimes follow prepositions
Where - can modify a noun place but cannot modify metaphorical place (condition,
situation, circumstances, arrangement)
When - modify a noun event or time; "in which" can also be used instead of when
Words used for two things vs. three or moreCorrect AnswersUse between only with two
things or people. Use among when talking about three or more things or people
Is it ok to insert a comma before because?Correct AnswersAcceptable if "because" is a
subordinating conjunction; in that case, it can be separated from a main clause by a
comma. If there are two possible interpretations without including a comma, there needs
to be a comma
If "because" is imperative for the rest of the sentence, don't separate it with a comma
Also, do not use "because" after "the reason". Use "the reason" plus "that"
Incorrect: The reason he left is because he was frustrated
Correct: The reason he left is that he was frustrated
Like vs. AsCorrect Answers"Like" is used to compare nouns, pronouns, or noun
phrases
"As" can be used to compare two clauses
Right: Like her brother, Ava aced the test
Right: As her brother did, Ava aced the test
,Comparative and SuperlativeCorrect AnswersDo not compare an adverb that ends in -ly
by changing the ending to -er
Wrong: He runs quicker than Jacob.
Right: He runs more quickly than Jacob.
Some adverbs that do not end in -ly are made into comparatives by adding -er
Right: He runs faster than Jacob.
Do not use a comparative adjective unless you have a than in the sentence
Wrong: With winter coming, I will have higher energy bills
Right: I will have higher bills than last year
PronounsCorrect Answers"This" and "These" are never used as standalone pronouns,
nor are "that" and "those"
Idioms for "ability..." and "capability..."Correct AnswersWrong: ability of doing...
Right: ability to do...
Right: capability of doing...
Compound SubjectsCorrect AnswersIf two nouns disagree in number with an "or"
conjunction, use the noun closest to the verb to determine agreement
Right: Either the manager or the employees take a break
Right: Either the employees or the manager takes a break
Colon rulesCorrect AnswersWhat comes before the colon must be able to stand alone
as a sentence
You can insert "namely" or "that is" after the colon, and the result would still be
acceptable
Right: I love listening to many kinds of music: namely, classical, rock, rap, and pop
Whatever needs explanation should be placed as close to the colon as possible
Worse: Three factors affect the rate of a reaction: concentration...
Better: The rate of a reaction is affected by three factors: concentration...
The clause after the colon must explain what precedes the colon
What to consume during testCorrect AnswersDuring the break after IR, eat something
with protein, fat, and complex carbs. During the break after Quant, drink glucose
(coconut water)
What property do all terminating decimals share?Correct AnswersThe simplified
denominator of the decimal must contain only 2's and 5's as prime factors. For example,
7/250 is a terminating decimal 0.028, as 250 equals to 2 x 5^3. Fraction 3/30 is also a
terminating decimal because 3/30 = 1/10 and denominator 10 = 2 x 5
"view X as Y" or "view X to be Y" ?Correct Answersview X as Y
, Ex: Many financial experts believe policy makers at the Federal Reserve, now *viewing*
the economy *as* balanced between moderate growth and low inflation, are almost
certain to leave interest rates unchanged.
Is "media" singular or plural?Correct AnswersPlural
Equation for the sum of the degree measures of the n interior angles of a
polygonCorrect Answers180(n - 2)
Each of 90 students participated in at least one of three track tryouts: high jump, long
jump, and 100-meter dash. If 20 students participated in the high jump, 40 students in
long-jump, and 60 students in 100-meter dash, and if 5 students participated in all three
tryouts, how many students participated in only two of these tryouts?Correct
AnswersLet x be the number who participated in exactly 1 of the tryouts, y be 2 of
tryouts, z be 3 of tryouts. Then x + y + z = 90 and x + 2y + 3z = 120. It is given that z =
5, so x + y = 85 and x + 2y = 105. Thus, y = *20*
Equation for the sum of the first n terms in an arithmetic sequenceCorrect Answers(n/2)
(A1 + An)
A train traveled from Station A to B at ave speed of 80 km/hr and from Station B to C at
ave speed 60 km/hr. If the train didn't stop at Station B, what was the average speed at
which the train traveled from Station A to C?
1) The distance that the train traveled from A to B was 4 times the distance from B to C
2) The amount of time it took the train to travel from A to B was 3 times the amount of
time that it took the train to travel from B to CCorrect Answers*Time = Dist / Speed*
d1/80 is the amt. of time it took to travel from A to B, and d2/60 is the amt. of time it took
to travel from B to C. We want to find average speed from A to C, given by Total Dist /
Total Time = (d1 + d2) / ( (d1/80) + (d2/60) )
1) gives d1 = 4d2, which plugged into the above yields an answer
2) gives d1/80 = 3(d2/60), or d1 = 4d2, same as above
Each statement alone is sufficient
A car traveling at a certain constant speed takes 2 seconds longer to travel 1 kilometer
than it would take to travel 1 kilometer at 75 kilometers per hour. At what speed, in
kilometers per hour, is the car traveling?Correct AnswersTraveling at 75 km/hr, the car
takes 1/75 hr to travel 1 km. In seconds, this equals 3600/75 = 48 seconds. So this car
takes 50 seconds to travel 1 km. In hours, this equals 50/3600 = 1/72 hr. Thus, the
speed of the car is 72 km/hr
Is x > 10^10?
1) x > 2^34
2) x = 2^35Correct AnswersTake square roots of both. 2^17 = 2^10 x 2^7 = 1024 x 128
> 10^5 = 100,000
Therefore each statement alone is sufficient.
What is 2^9? 2^8? List first ten roots of 2.Correct Answers2^9 = 512.
What are the first ten prime numbers?Correct Answers2, 3,5, 7, 11, 13, 17, 19, 23, 29
Sum of two primesCorrect AnswersAll prime numbers are odd, except the number 2.
Thus, the sum of any two primes will be even unless one of those primes is the number
2
If a sum of primes is odd, one of those primes must be the number 2
Counting total factorsCorrect AnswersIf a number has prime factorization a^w x b^y x
c^z (where a, b, and c are all prime), then the number has (w +1)(y + 1)(z + 1) different
factors
Perfect squaresCorrect Answers1) All perfect squares have an odd number of total
factors, which always sum up to an odd number
2) Prime factorization of a perfect square contains only even powers of primes
Should vs. MustCorrect AnswersMust = binding obligation
Should = moral obligation
Relative pronoun rulesCorrect AnswersThat - if the clause is essential, it must begin
with "that" rather than "which"
Who/whom - must modify people
Which - cannot modify people
Whose - can modify people or things
Which/whom - sometimes follow prepositions
Where - can modify a noun place but cannot modify metaphorical place (condition,
situation, circumstances, arrangement)
When - modify a noun event or time; "in which" can also be used instead of when
Words used for two things vs. three or moreCorrect AnswersUse between only with two
things or people. Use among when talking about three or more things or people
Is it ok to insert a comma before because?Correct AnswersAcceptable if "because" is a
subordinating conjunction; in that case, it can be separated from a main clause by a
comma. If there are two possible interpretations without including a comma, there needs
to be a comma
If "because" is imperative for the rest of the sentence, don't separate it with a comma
Also, do not use "because" after "the reason". Use "the reason" plus "that"
Incorrect: The reason he left is because he was frustrated
Correct: The reason he left is that he was frustrated
Like vs. AsCorrect Answers"Like" is used to compare nouns, pronouns, or noun
phrases
"As" can be used to compare two clauses
Right: Like her brother, Ava aced the test
Right: As her brother did, Ava aced the test
,Comparative and SuperlativeCorrect AnswersDo not compare an adverb that ends in -ly
by changing the ending to -er
Wrong: He runs quicker than Jacob.
Right: He runs more quickly than Jacob.
Some adverbs that do not end in -ly are made into comparatives by adding -er
Right: He runs faster than Jacob.
Do not use a comparative adjective unless you have a than in the sentence
Wrong: With winter coming, I will have higher energy bills
Right: I will have higher bills than last year
PronounsCorrect Answers"This" and "These" are never used as standalone pronouns,
nor are "that" and "those"
Idioms for "ability..." and "capability..."Correct AnswersWrong: ability of doing...
Right: ability to do...
Right: capability of doing...
Compound SubjectsCorrect AnswersIf two nouns disagree in number with an "or"
conjunction, use the noun closest to the verb to determine agreement
Right: Either the manager or the employees take a break
Right: Either the employees or the manager takes a break
Colon rulesCorrect AnswersWhat comes before the colon must be able to stand alone
as a sentence
You can insert "namely" or "that is" after the colon, and the result would still be
acceptable
Right: I love listening to many kinds of music: namely, classical, rock, rap, and pop
Whatever needs explanation should be placed as close to the colon as possible
Worse: Three factors affect the rate of a reaction: concentration...
Better: The rate of a reaction is affected by three factors: concentration...
The clause after the colon must explain what precedes the colon
What to consume during testCorrect AnswersDuring the break after IR, eat something
with protein, fat, and complex carbs. During the break after Quant, drink glucose
(coconut water)
What property do all terminating decimals share?Correct AnswersThe simplified
denominator of the decimal must contain only 2's and 5's as prime factors. For example,
7/250 is a terminating decimal 0.028, as 250 equals to 2 x 5^3. Fraction 3/30 is also a
terminating decimal because 3/30 = 1/10 and denominator 10 = 2 x 5
"view X as Y" or "view X to be Y" ?Correct Answersview X as Y
, Ex: Many financial experts believe policy makers at the Federal Reserve, now *viewing*
the economy *as* balanced between moderate growth and low inflation, are almost
certain to leave interest rates unchanged.
Is "media" singular or plural?Correct AnswersPlural
Equation for the sum of the degree measures of the n interior angles of a
polygonCorrect Answers180(n - 2)
Each of 90 students participated in at least one of three track tryouts: high jump, long
jump, and 100-meter dash. If 20 students participated in the high jump, 40 students in
long-jump, and 60 students in 100-meter dash, and if 5 students participated in all three
tryouts, how many students participated in only two of these tryouts?Correct
AnswersLet x be the number who participated in exactly 1 of the tryouts, y be 2 of
tryouts, z be 3 of tryouts. Then x + y + z = 90 and x + 2y + 3z = 120. It is given that z =
5, so x + y = 85 and x + 2y = 105. Thus, y = *20*
Equation for the sum of the first n terms in an arithmetic sequenceCorrect Answers(n/2)
(A1 + An)
A train traveled from Station A to B at ave speed of 80 km/hr and from Station B to C at
ave speed 60 km/hr. If the train didn't stop at Station B, what was the average speed at
which the train traveled from Station A to C?
1) The distance that the train traveled from A to B was 4 times the distance from B to C
2) The amount of time it took the train to travel from A to B was 3 times the amount of
time that it took the train to travel from B to CCorrect Answers*Time = Dist / Speed*
d1/80 is the amt. of time it took to travel from A to B, and d2/60 is the amt. of time it took
to travel from B to C. We want to find average speed from A to C, given by Total Dist /
Total Time = (d1 + d2) / ( (d1/80) + (d2/60) )
1) gives d1 = 4d2, which plugged into the above yields an answer
2) gives d1/80 = 3(d2/60), or d1 = 4d2, same as above
Each statement alone is sufficient
A car traveling at a certain constant speed takes 2 seconds longer to travel 1 kilometer
than it would take to travel 1 kilometer at 75 kilometers per hour. At what speed, in
kilometers per hour, is the car traveling?Correct AnswersTraveling at 75 km/hr, the car
takes 1/75 hr to travel 1 km. In seconds, this equals 3600/75 = 48 seconds. So this car
takes 50 seconds to travel 1 km. In hours, this equals 50/3600 = 1/72 hr. Thus, the
speed of the car is 72 km/hr
Is x > 10^10?
1) x > 2^34
2) x = 2^35Correct AnswersTake square roots of both. 2^17 = 2^10 x 2^7 = 1024 x 128
> 10^5 = 100,000
Therefore each statement alone is sufficient.
What is 2^9? 2^8? List first ten roots of 2.Correct Answers2^9 = 512.
