statistics
posted by uma .
A class consists of 50 students, 20 of them are girls and boys, 10 them are rich and remaining poor, 5 of them are fair complxioned, 3 are intelligent. What is the probability of selecting a fair complexioned rich intelligient girl?

Proofread your questions before you post them.
"20 of them are girls and boys"?
I will asume 20 are girls and 30 are boys.
P(fair) = 5/50
p(rich) = 10/50
p(IQ) = 3/50
P(girl) = 20/50
Probability of all events occurring is found by multiplying the individual probabilities. 
.25
.125
.312
.687