the answer for this question is option D but if we simply apply the formula we get 20 so i am not getting this
Look to maximize the intersection. Can you have an intersection greater than 20? If so, what effect does that have on the household that have no daughter nor sons (none).
What formula are you applying? Are you factoring in “Neither”?
well here i used total=A+B-both
It’s A + B - Both + NEITHER = Total
Here, do you know what neither is?