Consider that the probability that a student is taking both geometry and chemistry class is the product of the probability for geometry class by the proability for chemistry class.
If the probability that a student is taking a chemistry
class and a geometry class is 0.18, and the probability that a student is taking a geometry class is 0.24, you have:
0.24x = 0.18
where x is the probability a student is taking a chemistry class.
Solve the previous equation for x:
0.24x = 0.18 divide by 0.24 both sides
x = 0.18/0.24
x = 0.75
