WAEC 2021 · Paper 2 · Q1

(a)
Mr Sarfo borrowed $25,000.00 from AFIAK Financial Services at $21\%$ simple interest per annum for 3 years. If he was able to pay back the loan in 2 years at equal yearly instalments, how much did he pay each year?
(b)
Two consecutive numbers are such that the sum of thrice the smaller and twice the larger is 17. Find, correct to three significant figures, the smaller number as a percentage of the sum of the two numbers.

Worked solution (try it first)

(a)

The loan was agreed at $21\%$ simple interest for 3 years.
Interest $= \frac{25\,000 \times 21 \times 3}{100}$
$= 15\,750$ , that is $15,750.
So the total to repay is $25\,000 + 15\,750 = 40\,750$ , that is $40,750.
He repaid it in 2 equal yearly instalments: $\frac{40\,750}{2} = 20\,375$ .
He paid $20,375.00 each year.

(b)

Let the smaller number be $x$ .
The next consecutive number is $x + 1$ .
Thrice the smaller plus twice the larger is 17: $3x + 2(x + 1) = 17$ .
So $5x + 2 = 17$ , $5x = 15$ and $x = 3$ .
The numbers are 3 and 4, with sum 7.
The smaller as a percentage of the sum: $\frac37 \times 100\% = 42.857\ldots\%$ .
Correct to three significant figures: $42.9\%$ .

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