Admission Tests Admission Tests Certifications GMAT-QUANTITIVE Questions & Answers

• Question 351:

  In a blue jar there are red, white and green balls. The probability of drawing a red ball is 1/5. The

  probability of drawing a red ball, returning it, and then drawing a white ball is 1/10.

  What is the probability of drawing a white ball?

  A. 1/5.

  B. ½.

  C. 1/3.

  D. 3/10.

  E. ¼.

  Correct Answer: B

  Indicate A as the probability of drawing a white ball from the jar.

  The probability of drawing a red ball is 1/5.

  The probability of drawing both events is 1/10 so, 1/5 x A = 1/10.

  Therefore A = ½.

• Question 352:

  Out of a classroom of 6 boys and 4 girls the teacher picks a president for the student board, a vice president and a secretary. What is the probability that only girls will be elected?

  A. 8/125.

  B. 2/5.

  C. 1/30.

  D. 1/720.

  E. 13/48.

  Correct Answer: C

  The basic principle of this question is that one person can't be elected to more than one part, therefore

  when picking a person for a job the “inventory” of remaining people is growing smaller.

  The probability of picking a girl for the first job is 4/10 = 2/5.

  The probability of picking a girl for the second job is (4-1)/(10-1) = 3/9.

  The probability of picking a girl for the third job is (3-1)/(9-1) = 1/4.

  The probability of all three events happening is: 2/5 x 3/9 x ¼ = 1/30.

• Question 353:

  The probability of Sam passing the exam is 1/4. The probability of Sam passing the exam and Michael passing the driving test is 1/6.

  What is the probability of Michael passing his driving test?

  A. 1/24.

  B. 1/2.

  C. 1/3.

  D. 2/3.

  E. 2/5

  Correct Answer: D

  Indicate A as the probability of Michael passing the driving test. The probability of Sam passing the test is 1/4, the probability of both events happening together is 1/6 so: 1/4 x A = 1/6 therefore A = 2/3.

• Question 354:

  In a deck of cards there are 52 cards numbered from 1 to 13. There are 4 cards of each number in the deck. If you insert 12 more cards with the number 10 on them and you shuffle the deck really good, what is the probability to pull out a card with a number 10 on it?

  A. 1/4.

  B. 4/17.

  C. 5/29.

  D. 4/13.

  E. 1/3.

  Correct Answer: A

  The total number of cards in the new deck is 12 +52 = 64.

  There are (4 + 12 = 16) cards with the number 10.

  The probability of drawing a 10 numbered card is 16/64 = 1/4.

• Question 355:

  There are 18 balls in a jar. You take out 3 blue balls without putting them back inside, and now the probability of pulling out a blue ball is 1/5. How many blue balls were there in the beginning?

  A. 9.

  B. 8.

  C. 7.

  D. 12.

  E. 6.

  Correct Answer: E

  After taking out 3 balls there are 15 left. 15/5 = 3 blue balls is the number of left after we took out 3 therefore there were 6 in the beginning.

• Question 356:

  Danny, Doris and Dolly flipped a coin 5 times and each time the coin landed on "heads". Dolly bet that on the sixth time the coin will land on "tails", what is the probability that she's right?

  A. 1.

  B. ?

  C. ?

  D. ?

  E. 1/3.

  Correct Answer: B

  The probability of the coin is independent on its previous outcomes and therefore the probability for "head" or "tail" is always ?

• Question 357:

  A and B are numbers between 1 and 9. What is ABAB/AB?

  (AB is a two-digit number and ABAB is a 4-digit number).

  A. 11

  B. BAB

  C. 101

  D. AB

  E. 100.

  Correct Answer: C

  Plug in numbers: A = 1, B = 2 AB = 12, ABAB = 1212. 1212/12 = 101.

• Question 358:

  V, W, X, Y and Z are numbers between 0 and 9.

  If XYZ / 15 = WV and V-W=X (WV is a 2 digit number, XYZ is a 3 digit number), which of the following numbers can represent XYZ?

  A. 321

  B. 215

  C. 633

  D. 570

  E. 414

  Correct Answer: D

  We see that XYZ should be equally dividable by 15, or by 5 and 3. The only number that fits those conditions is 570.

• Question 359:

  A, B and C are different numbers, each between 0 and 9.

  If B = C+2, what is BCA -CBA- (CBA and BCA are both 3 digit numbers).

  A. 170

  B. 180

  C. 173

  D. 198

  E. 146

  Correct Answer: B

  Let's put in some numbers. C = 1, so B = 1 + 2 = 3. There is no information about A so we'll leave it as A. BCA -CBA = 31A -13A = 180. B is the answer.

• Question 360:

  B and A are consecutive numbers. If A + B + X =15 than what is true about X?

  A. It can be equally divided by 5.

  B. It can be equally divided by 3.

  C. Positive.

  D. Even.

  E. Odd.

  Correct Answer: D

  A + B is an odd number; in order for the sum to be equal to 15 X must be an even number.