# Buying, selling, profit and wages · Year 10

> Buying, selling, profit and wages, Year 10: Buying and selling and more. Explanation, worked examples and free practice for the national curriculum in England.

In Buying, selling, profit and wages (Year 10) you practise 4 skills: Buying and selling · Profit and loss · Wages and overtime · Unit prices.

When a price goes up or down by a percent, first work out that percent of the price, then add it on or take it away. A discount of 20 percent on a price of 300 is 60, so the sale price is 240.

The income is the money that comes in from a sale. The profit is the income minus what was paid. When more was paid than came in, there is a loss.

The pay for a day is the number of hours times the pay for an hour. Many workplaces pay more for overtime, so work out the pay for each group of hours separately and add them. Every country’s law sets its own minimum wage and its own pay for overtime.

To compare packs of different sizes, work out the price of the same amount in each, such as a kilogram or a litre. The bigger pack is not always cheaper.

**Tip:** When an amount of money is not a whole number, write it with two digits after the decimal point.

## What you learn

### Buying and selling

- Example: The price of a bike in a shop was £140, and it went up by 15 percent. What is the new price?
- Answer: £161
- Solution: 140 × 15 ÷ 100 = 21 , so 140 + 21 = 161 .

### Profit and loss

- Example: A market stall bought 34 balls at £39 each, and sold all of them at £41 each. How much profit did the stall make?
- Answer: £68
- Solution: The cost: 34 × 39 = 1326 . The income: 34 × 41 = 1394 . The profit: 1394 − 1326 = 68 .

### Wages and overtime

- Example: The pay at a workplace is £48 an hour. How much is earned for a working day of 4 hours?
- Answer: £192
- Solution: 4 × 48 = 192

### Unit prices

- Example: A 250 ml bottle of milk costs £7. What is the price of a litre of milk?
- Answer: £28
- Solution: 7 ÷ 250 × 1000 = 28

The exercises are made by rules and the answers are worked out in code. The topic follows the national curriculum in England: mathematics (key stages 3 and 4).

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