if 5 a = 3125, then the value of 5(a-3) is :	Choose the correct choice from the following answers:
A) 25 B) 125 C) 625 D) 1625 E) none of these

Rationale: solution 5 a = 3125 ⇔ 5 a = 5 a ⇔ a = 5 . ∴ 5 ( a - 3 ) = 5 ( 5 - 3 ) = 52 = 25 . answer a
Answer: A