GMAT prep PS question

[mlane25269]

Can someone explain? Thanks!

[Vemuri]

If 2 crowns equal 4 pounds. Then 9 crowns should equal 18 pounds (since they are in 1:2 ratio).

Answer should be A

[gmat740]

2c=3s =4p

so, 4p=2c

p=c/2

18p = 18*(C/2) = 9C

hope this Helps

[rossmj]

The easiest way to see this is to set up the ratios as fractions and multiply them, the 3s cancel out and you get the 1:2 ratio