A pair of numbers is picked up randomly (without replacement) from the set {1, 2, 3,5, 7, 11, 12, 13, 17, 19). The probability that the number 11 was picked given that the sum of the numbers was even is nearly

Let Abe the event that 11 is picked and B be the event that sum is even. The number of ways of selecting 11 along with one more odd number is n(A∩B)=7C1. The number of ways of selecting either two even numbers or selecting two odd numbers is n(B)=1+8C2. ∴ P(A/B)=P(A∩B)P(B)=729=0.24