Question

you have a 90% chance of passing this IE 223 course if you get 

an 85 or higher on your midterm test. However, if you think you only have a 50% 

chance of scoring an 85 or higher in taking the test. Calculate the chances that 

both of your scores are 85 or higher.

Answer 1

Probability of getting 85 or higher in mid term term $P(A)=0.9$

Probability of scoring an 85 or higher in taking the test $P(B)=0.5$

So The probability of getting 85 or higher $=P(A).P(B$ ) ( As A and B are independent events)

$=(0.9).(0.5)=(0.45)=45$ %