In a game of billiards, A can give B, 15 points in 60 and A can give C, 20 points in 60. How many points can B give C in a game of 90?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 10 points
“A can give B 15 points in 60” means that when A scores 60, B scores 60 − 15 = 45. In the same way, when A scores 60, C scores 60 − 20 = 40. So, when B scores 45, C scores 40:
\(B : C = 45 : 40 = 9 : 8\)
In a game of 90, when B scores 90:
\( \displaystyle \text{C scores } 90 \times \frac{8}{9} = 80 \)
So B can give C 90 − 80 = 10 points.