Question 950575
P(B|A)=P(A_and_B)/P(A)
However since A and B are independent,
{{{P(A_and_B)=P(A)*P(B)}}}
so 
{{{P(A_and_B)/P(A)=P(B)}}}
and
P(B|A)={{{P(B)=249/999}}}