Please explain each step and write clear According to border

Please explain each step and write clear.

According to border patrol statistics, the probability that a U.S. resident traveled to Canada is 18%, to Mexico is 9% and both countries is 4%.

(a) What is the probability that someone that traveled to Mexico has visited Canada too?

(b) Are travel to Canada and Mexico independent events? Explain.

M - Travel to Mexico

C - Travel to Canada

a.) P(C|M) = P(C n M)/P(M) = 0.04/0.09 = 4/9 = 0.4444

b.) P(M n C) = 0.04

P(M)*P(C) = (0.09)*(0.18) = 0.0162

Since P(M n C) is not equal to P(M)*P(C), M and C are not independent events.

c.) Since P(M n C) = 0.04 , which is non zero, M and C are not mutually exclusive events