At a game of billiards, A can give B 20 points in 60 and A can give C 15 points in 60. How many points can C give B in a game of 90 ?
50
40
10
15
Explanation:
a:b = 60:40
a:c = 60:45
c/a x a/b = 45/60 x 60/40 = 45/40 = 90/80
So C gives B => 10 points.
a:b = 60:40
a:c = 60:45
c/a x a/b = 45/60 x 60/40 = 45/40 = 90/80
So C gives B => 10 points.