The difference between the value of a number increased by 12.5% and the value of the original number decreased by 25% is 30. What is the original number?
Choose the correct option:
A) 60	B) 80	C) 40	D) 120	E) 160

Rationale: "explanatory answer let the original number be x . let a be the value obtained when x is increased by 12.5 % . therefore , a = x + 12.5 % of x let b be the value obtained when x is decreased by 25 % . therefore , b = x - 25 % of x the question states that a - b = 30 i . e . , x + 12.5 % of x - ( x - 25 % of x ) = 30 x + 12.5 % of x - x + 25 % of x = 30 37.5 % of x = 30 x = 30 / 37.5 * 100 = 80 the correct choice is ( b )"
Answer: B