Question

A high school has 35 students who play only stringed instruments,

Answer 1

Answer:

$\frac{10}{11}$

Step-by-step explanation:

Note : the total number of students is 55

___________________________

$p\left( A\cup B\right) =p\left( A\right) +p\left( B\right) -p\left( A\cap B\right)$

p(A) = 40/55

p(B) = 15/55

$p\left( A\cap B\right) =\frac{5}{55}$

Therefore,

$p\left( A\cup B\right) =p\left( A\right) +p\left( B\right) -p\left( A\cap B\right)$

               $=\frac{40}{55} +\frac{15}{55} -\frac{5}{55}$

               $=\frac{50}{55}$

               $=\frac{10}{11}$