Answer
a. $0.295$
b. $0.419$
c. $0.093$
Work Step by Step
The number of total schools is 83057
a. 50 or fewer computers
There are 24501 schools with 50 or fewer computers, so the probability is $p=\frac{24501}{83057}=0.295$
b. More than 100 computers
There are 34803 schools with more than 100 computers, so the probability is $p=\frac{34803}{83057}=0.419$
c. No more than 20 computers
There are 7760 schools with no more than 20 computers, so the probability is $p=\frac{7760}{83057}=0.093$