The sum of two positive integers A and B is 10 (A is not equal to B). What will be the probability t

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27 Jul 2011 Probability

The sum of two positive integers A and B is 10 (A is not equal to B). What will be the probability to have a case in which their product is maximum.

OPtion

1) 1
2) 1/5
3) 1/4
4) 3/4
5) 2/5
6) 4/7
7) 1/7
8) 2/3
9) 3/8
10) None of these

Solution

Possible cases are
(9,1)(8,2)(7,3)(6,4)(4,6)(3,7)(2,8)(1,9)
Only the middlemost two (6,4)(4,6) has the maximum product

thus probability = 2/8 = 1/4

Correct Option: 3 Best Solution (4)