if set a ={2,3,5,7} and two numbers are selected at random from A(duplicates allowed), then what is the probability that the sum of the numbers is even?  Choose the correct option:  A) 1/8  B) 13/16  C) 5/12  D) 5/8  E) 2/3
Sum of the two numbers would be even if   (1) Both digits are even.   (2) Both digit are odd.   (1) only one case is there: 22   (2) Following cases are there: 33, 35, 37 - 3 nos. Similarly 3 nos, with 5 (53, 55, 57) and 3 nos. with 7 (73, 75, 77)   Total 10 nos.   Total nos. that can be formed (repetition is allowed)   {1st no. can be chosen in 4 ways. Similarly 2nd no. can be chosen in 4 ways. Total  4*4= 
<gadget id="calculator"> 4*4</gadget>
<output>16</output>
16 ways}   Prob : 10/16= 5/8   5/8 is the answer.
<result>D</result>
if set a ={2,3,5,7} and two numbers are selected at random from A(duplicates allowed), then what is the probability that the sum of the numbers is even?