If the probability that A will live 15 yr is 7/8 and that B will live 15 yr is 9/10, then what is the probability that both will live after 15 yr?

Here, n(5) = {a, e, i,o, u}
and E = Event of selecting the vowel i = {i}
? P(E)= n(E)/n(S) = 1/5

Total ways = 52
There is one queen of club and one king of heart favourable ways = 1 + 1 = 2.
? Required probability = 2/52 = 1/26

No of white balls = 7
Red balls = 9
Total no. of balls = 7 + 9 = 16
Probability of drawing a white ball = 7/16

? Total no. of favourable cases i,e., (5, 10, 15, 20, 25, 30, ....., 105, 110, 115, 120) = 24.
? Reqd . Prob = 24/120 = 1/5

Probability of getting head in one trail = 1/2
? Reqd Probability of getting heads in both the trails = 1/2 x 1/2 = 1/4

Total number of letters = n(S) = 11
whereas, number of vowels = n(E) = 4
? Required probability = n(E)/n(s) = 4/11

Total number of cards n(S) = 52
Number of red cards n(E) = 26
? P(E) = n(E)/n(S) = 26/52 = 1/2

n(S) = 6, n(E) = (4, 6) = 2
? P(E) = 2/6 = 1/3

n(S) = 36
n(E) = {(5,6), (6,5)} = 2
? p(E) = n(E) / n(S) = 2/36 = 1/18

Clearly, n(S) = 20 and E = { 3, 6, 9, 12, 15, 18, 7, 14 } i.e., n(E) = 8

? P(E) = n(E)/ n(S) = 8/20 = 2/5