Question 960121
Probability(P) that Helen gets into school B given that she gets into school is,
P(A given B) = 9/14 * A = 3/7 = 9A/14 = 3/7, then
cross multiply fractions
63A = 42
A = 42 / 63 = 6 / 9 = 2/3 and
2/3 * 9/14 = 18 / 42 = 3/7
answer checks