At Joseph Middle School, the probability that a boy takes English and Science is 0.087. The probability that a boy takes English is 0.68. What is the probability that a boy takes Science given that the boy is taking English?

The conditional probability of S given E is

P(S|E)=P(S∩E)/P(E)
Here
P(S∩E)=0.087
P(E)=0.68
So
P(S|E)=0.087/0.68=0.128 (approx.)