If 0.25 of a number is equal to 0.05 of another number, the ratio of the numbers is :  Choose the correct choice from the following.
A) 2 : 5  B) 3 : 4  C) 1 : 5  D) 20 : 5  E) 30 : 7

Rationale: "0.25 a = 0.05 b - > a / b = 0.05 / 0.25 = 5 / 25 = 1 / 5 : . a : b = 1 : 5 answer : c"
Answer: C