If 2.5 of a number is equal to 0.75 of another number, the ratio of the numbers is :	Select the correct option.
A) 2 : 3 B) 3 : 4 C) 3 : 10 D) 20 : 3 E) 30 : 7

Rationale: "2.5 a = 0.75 b - > a / b = 0.75 / 2.5 = 75 / 250 = 3 / 10 : . a : b = 3 : 10 answer : c"
Answer: C