Question

Work out the percentage change when a price of £10is decreased by £7

Answer 1

Hey there!

To start, percent change is calculate by the formula
`(amount of change)/(Old Value)` * 100.

In this case, the amount of change that occurred is 10-7, or 3.

Your setup should look like this:

(3/10)*100

This would be equal to 0.3 * 100 which simplifies to 30 or 30% (the percent change).

Hope this helps!

Answer 2

Answer: 30% decrease

Explanation: To find the percent decrease, we divide the amount of change by the original number.

The amount of change is the difference between the two numbers which in this case is 10 - 7 and the original number is 10.

So we have
`(10 - 7)/(10)` or
`(3)/(10)` when we simplify the numerator.

So we're left with 3 divided by 10 and dividing 10 into 3 gives us 0.3.

Remember however that our problem is asking for a percent, not a decimal.

So we need to write 0.3 as a percent by moving the decimal point

two places to the right to get 30%.

So when a number changes from 10 to 7, it has decreased by 30%.