JAMB Mathematics 2015 Paper

Concept:Compound interest uses the formula $A = P\left(1 + \frac{r}{100}\right)^{n}$, where $P$ is the principal, $r$ is the rate, and $n$ is the number of years.Explanation:Substitute the given values: $P = 126$, $r = 4$, and $n = 2$.Write the formula with these values:$$A = 126\left(1 + \frac{4}{100}\right)^{2}$$Add the terms inside the bracket using a common denominator of 100:$$1 + \frac{4}{100} = \frac{100 + 4}{100} = \frac{104}{100} = 1.04$$So the expression becomes:$$A = 126(1.04)^{2}$$Square $1.04$:$$(1.04)^{2} = 1.04 \times 1.04 = 1.0816$$Multiply by 126:$$A = 126 \times 1.0816 = 136.2816$$Round to the nearest kobo: $A \approx 136.30$.Answer:The amount is N136.30K.