Kindly answer all In a survey conducted by school authorities in elementary school children ,81% of children said that the elementary courses were sometimes or always complex .randomly 200children...

Kindly answer all

In a survey conducted by school authorities in elementary school children ,81% of children  said that the elementary courses were  sometimes or always complex .randomly 200children were selected

1  find the prob that 150 or less children find the courses  complex

2  find the prob that more than 160 children find the courses complex

3 find the prob that the no of children who find the courses complex lie between  147 amd 157 inclusive