this question is from a princeton test CD-Rom and unfortunately they don't explain the answers.
10 slips of paper numbered 1-10 are placed in a bag.
if 3 slips are chosen at random and one is the number 7, what is the sum of the numbers on the 3 slips?
(1) The sum of two of the numbers is 16
(2) The sum of two of the numbers is 14
I think the answer is E. But they say the answer is B.
A+B = 16, could potentially be (10+6)
7+A = 16, A = 9, but what is B? what is the total sum?
7+B = 16, B = 9, but what is A? what is the total sum?
A+B = 14
7+A = 14, this means that A=7, but can not because numbered 1-10
7+B = 14, this means that B=7, but can not because numbered 1-10
therefore, A+B=10+4 or vise versa, either way, sum will equal to 21.