JAMB Mathematics 2017 Paper

Concept:Simple interest is a fixed percentage of the principal paid each year, and the amount is the principal plus all the interest earned.Explanation:Let the principal be $P$.Given: amount $A = \text{₦}5{,}500$, rate $R = 2\%$ per annum, and time $T = 5$ years.The simple interest formula is $I = \frac{PRT}{100}$.Substitute $R = 2$ and $T = 5$: $I = \frac{P \times 2 \times 5}{100} = \frac{10P}{100} = \frac{P}{10}$.Since the amount is $A = P + I$, we get $5500 = P + \frac{P}{10}$.Combine the terms on the right: $P + \frac{P}{10} = \frac{11P}{10}$.Thus $5500 = \frac{11P}{10}$.Multiply both sides by $10$: $55{,}000 = 11P$.Divide both sides by $11$: $P = \frac{55{,}000}{11} = 5{,}000$.Answer:The principal is $\text{₦}5{,}000$, so the correct option is B.