Question

Suppose is a semester that 38% of students at a college failed mathematics, 27% failed physics, and 9% failed both. A student is selected at random.

a)If a student failed physics, what is the probability that he or she failed math?
b)If a student failed math, what is the probability he or she failed physics?
c)What is the probability that he or she failed math or physics?

Answer 1

Hello,

A) failed in Phys: 27 failed in Math ==> intersection : 9/27=1/3

B)Failed in Math 38 ,failed in Phys ==>9/38

C) M∪P=M+P-M∩P= (38+27-9)/100=56/100=14/25

Probabiliy is hard for me.