Tennis or Rounders? KS2 Level 6 Question

Today we have the age old question of the summer - tennis or rounders?

This was taken from the 2015 KS2 Level 6 paper for able children

20% of the children in a sports club play tennis

25% of the children who play tennis also play rounders

There are 8 children in the club who play both tennis and rounders

How many children are there in the sports club altogether?