Answer:
3/20
Explanation:
First we need to find a common denominator, and since 4*5=20 then 20 is he common denominator.
convert the fractions to twentieths so
3/5*4/4
12/20
1/4*5/5
5/20
now add 12/20+5/20
17/20
that is how many students are doing sports
so subtract 20-17
you get 3/20 students play basketball since you can't simplify that