Jo's collection contains US, Indian and British stamps. If the ratio of US to Indian stamps is 5 to 2 and the ratio of Indian to British stamps is 5 to 1, what is the ratio of US to British stamps?  Pick one.
A) 25 : 8	B) 25 : 0	C) 25 : 8	D) 25 : 2	E) 25 : 9
Indian stamps are common to both ratios. Multiply both ratios by factors such that the Indian stamps are represented by the same number.   US : Indian = 5 : 2, and Indian : British = 5 : 1. Multiply the first by 5, and the second by 2.   Now US : Indian = 25 : 10, and Indian : British = 10 : 2   Hence the two ratios can be combined and US : British = 25 : 2   Answer:25 : 2
<result>D</result>
Jo's collection contains US, Indian and British stamps. If the ratio of US to Indian stamps is 5 to 2 and the ratio of Indian to British stamps is 5 to 1, what is the ratio of US to British stamps?