WAEC 2022 · Paper 2 · Q8

Item	Food and drinks	Fuel	Rent	Building project	Education	Savings
Percentage (%)	35	7.5	10	15	17.5

The table shows the monthly expenditure (in percentage) of Mr. Okafor's salary.

(a)
Calculate the percentage of Mr. Okafor's salary that was put into savings.
(b)
Illustrate the information on a pie chart.
Model answer
Each $1\%$ is $3.6^\circ$ , so the angles are food and drinks $126^\circ$ , fuel $27^\circ$ , rent $36^\circ$ , building project $54^\circ$ , education $63^\circ$ and savings $54^\circ$ (total $360^\circ$ ). Draw each sector with a protractor and label it.
(c)
If Mr. Okafor's annual gross salary is $28,800.00 and he pays tax of $12\%$ , calculate: (i) his monthly tax; (ii) the amount saved each month.
Separate values with commas, e.g. 3, −2

Worked solution (try it first)

The percentages must add up to 100.
The others total $35 + 7.5 + 10 + 15 + 17.5 = 85$ , so savings are $100 - 85 = 15\%$ .

$100\%$ is the whole circle, $360^\circ$ , so $1\% = 3.6^\circ$ .
Food and drinks $35 \times 3.6^\circ = 126^\circ$ , fuel $27^\circ$ , rent $36^\circ$ , building project $54^\circ$ , education $63^\circ$ , savings $54^\circ$ .
Check: they add up to $360^\circ$ .
Draw the sectors with a protractor and label each with the item and its angle.

Annual tax $= 12\%$ of $28,800 $= 0.12 \times 28\,800$
$= \text{\textdollar}3,456$ .
Monthly tax $= \frac{3456}{12}$
$= \text{\textdollar}288.00$ .

After tax he has $28\,800 - 3456 = \text{\textdollar}25,344$ a year, which is $\frac{25\,344}{12} = \text{\textdollar}2,112$ a month.
He saves $15\%$ of it: $0.15 \times 2112 = \text{\textdollar}316.80$ a month.