Percentages and Ratios
Primary 6 · Mathematics
Percentages and Ratios
Lesson 4 of 6
15 min
Let's begin
Mutesi buys a basket of 50 avocados for 6 000 Frw at Musanze market. Back in her village she sells each avocado for 150 Frw. At the end of the day she counts her money. Did she gain or lose, and was it a good day's business?
Mutesi's avocados.
Selling price = 50 × 150 = 7 500 Frw.
Cost price = 6 000 Frw.
7 500 is more than 6 000, so she made a profit of 7 500 − 6 000 = 1 500 Frw.
To judge whether 1 500 Frw is a lot, compare it with what she paid:
percentage profit = profit ÷ cost price × 100
percentage loss = loss ÷ cost price × 100
Mutesi: 1 500 ÷ 6 000 × 100 = 25% profit.
Worked example
(loss). Habimana bought a bicycle for 80 000 Frw. Later he sold it for 68 000 Frw.
Loss = 80 000 − 68 000 = 12 000 Frw.
Percentage loss = 12 000 ÷ 80 000 × 100 = 15%.
Gatete buys a radio for 25 000 Frw and wants a profit of 20%.
Profit = 20% of 25 000 = 5 000 Frw.
Selling price = 25 000 + 5 000 = 30 000 Frw. You can also do it in one step: 120% of 25 000 = 1.2 × 25 000 = 30 000 Frw.
A discount is an amount taken off the marked price. A shirt is marked 15 000 Frw, and the shop gives a 10% discount.
Discount = 10% of 15 000 = 1 500 Frw.
You pay 15 000 − 1 500 = 13 500 Frw.
Tip
Profit and loss percentages are always "out of" the cost price, the money that was first paid. Never divide by the selling price.
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Quick check
Habimana buys a goat for 40 000 Frw and sells it for 50 000 Frw. What is his percentage profit?