The answer is 5 children.
Detailed Explanation
The problem states:
"A mother has 4 daughters. Each daughter has a brother. How many children does the mother have?"
Many people read quickly and assume that each daughter has a different brother, which would give:
4 daughters
4 brothers
= 8 children ❌
But that's not what it says.
The phrase "Each daughter has a brother" simply means that each of the four daughters has a brother, and it could very well be the same boy.
So we have:
4 daughters
1 brother (common to all 4 daughters)
