Answer:
the answer is 40 boys
Explanation:
Let's say there are x boys who play both cards and carrom.
We setup up an equation that involved all information given and x.
Boys who only play cards = 45-x
Boys who only play carrom = 20-x
Boys who play both = x
Add there together and you should get 60, which is the total number of students in the class.
(45-x)+(20-x)+x=60
65-x=60
x=5
Boys who only play cards=45-x=45–5=40
hope it helps you