There is a relationship between the three numbers in each circle. What number is missing from the last circle?

On your bike

John and Harry decided to ride 24 miles on their bikes. John rode at the same speed all the way. Harry rode from A to B at double John’s speed; from B to C at the same speed as John, and from C back to A at half John’s speed. Who was first to get back to A? How far ahead was he?

Brainteaser solutions

Missing numbers

The three numbers in each circle has a total of 25. The missing number in the last circle is 7.

On your bike

John was first. He was two miles ahead of Harry.