Six cards numbered from 1 to 6 are placed in an empty bowl. First one card is drawn and then put back into the bowl; then a second card is drawn. If the cards are drawn at random and if the sum of the numbers on the cards is 8, what is the probability that one of the two cards drawn is numbered 5?
A) 1/6
B) 1/5
C) 1/3
D) 2/5
E) 2/3
ANS: D
Would like some advice on how to set up the question. I understand that only 5 numbers out of 6 are involved in contributing to a sum of 8.
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Ways to get a sum of 8:ruwan_s wrote:Six cards numbered from 1 to 6 are placed in an empty bowl. First one card is drawn and then put back into the bowl; then a second card is drawn. If the cards are drawn at random and if the sum of the numbers on the cards is 8, what is the probability that one of the two cards drawn is numbered 5?
A) 1/6
B) 1/5
C) 1/3
D) 2/5
E) 2/3
2, 6
3, 5
4, 4
5, 3
6, 2
As the options in red indicate, 2 of the 5 ways include a card numbered 5.
Thus:
P(a card numbered 5 is drawn) = 2/5.
The correct answer is D.
Last edited by GMATGuruNY on Mon May 30, 2016 2:32 pm, edited 1 time in total.
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
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Thank you Mitch, you made it look so easy!GMATGuruNY wrote:Way to get a sum of 8:ruwan_s wrote:Six cards numbered from 1 to 6 are placed in an empty bowl. First one card is drawn and then put back into the bowl; then a second card is drawn. If the cards are drawn at random and if the sum of the numbers on the cards is 8, what is the probability that one of the two cards drawn is numbered 5?
A) 1/6
B) 1/5
C) 1/3
D) 2/5
E) 2/3
2, 6
3, 5
4, 4
5, 3
6, 2
As the options in red indicate, 2 of the 5 ways include a card numbered 5.
Thus:
P(a card numbered 5 is drawn) = 2/5.
The correct answer is D.
