JAMB Mathematics 1979 Question 44

Question 44

Ratio, Percentages and Rates

The size of a quantity first doubles and then increases by a further 16%. After a short time its size decreases by 16%. What is the net increase in size of the quantity?

A.⁵⁹³⁰⁰/₆₂₅ %
B.⁵⁰⁹⁰⁰/₆₂₅ %
C.200%
D.+ 100%
E.−100%

Show the answer and explanation

Answer: A (⁵⁹³⁰⁰/₆₂₅ %)

Explanation

Multiply the factors: 2 × 1.16 × 0.84 = 1.9488. The increase is 0.9488 = 94.88%, and 59300 ÷ 625 = 94.88.