Question

A bag-I contains four cards numbered 1, 3, 5 and 7 respectively. Another bag-II contains three
cards numbered 2, 4 and 6 respectively. A card is drawn at random from each bag. Find the
probability that the sum of two cards drawn is 9.

Answer 1

3+6, 5+4, 7+2 ( 3 cases)
total cases= 4*3
P=3/12 = .25

Answer 2

The probability of getting the sum of two cards drawn as 9 would be 1/4

The total number of possible cases would be 4*3  = 12

i.e.

1, 2       1,4      1,6    3,2    3,4      3,6       5,2      5,4     5,6        7,2      7,4     7,6

Total favorable cases i.e. in which the sum of numbers is equal to 9 are:

3,6     5,4      7,2

Total cases = 12

favorable cases = 3

Probability of getting a favorable case = 3/12 = 1/4

= 0.25