Question

out of 100 students, 27 are taking calculus, 26 are taking French, and 13 are taking both calculus and French. If a student is picked at random, what is the probability that the student is taking calculus or French? write your answer in fraction form

Answer 1

Determine the probability for taking calculus.

$P(C)=\frac{27}{100}$

Determine the probability for taking French.

$P(F)=\frac{26}{100}$

Determine the probability for taking calculus and French.

$P(F\text{ and C)=}\frac{13}{100}$

Determine the probability for taking Calculus or French.

$\begin{gathered} P(C\text{ or F)=P(C)+P(F)-P(C and F)} \\ =\frac{27}{100}+\frac{26}{100}-\frac{13}{100} \\ =\frac{27+26-13}{100} \\ =\frac{40}{100} \\ =\frac{2}{5} \end{gathered}$

So answer is 2/5.