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ALGEBRA · HLIntroduction
Percentages · Second Year

Percentages

Second Year  ·  Percentage of an amount & increase  ·  Tap NEXT to begin

Section 1 of 2

Percentage of an Amount

‘Per cent’ means out of $100$. Turn the percent into a decimal and multiply.

Worked example — a percentage of money

Find $18\%$ of €$250$.
$0.18 \times 250$
€$45$

Worked example — a smaller percentage

Find $6\%$ of $31.5$ m.
$0.06 \times 31.5$
$1.89$ m
Section 2 of 2

Percentage Increase

The unitary method
$100\%$ is the whole. Find $1\%$ by dividing by $100$, then multiply up to the percentage you need.

Now you try

You try
Find the value after a $14\%$ increase on €$360$.
Pen and paper out — try it before you reveal.
$100\% = 360$, so $1\% = 3.60$
$114\% = 360 \times 1.14$
€$410.40$
€$410.40$
You try
A car costs €$8300$ and is sold at a $9\%$ profit. Find the selling price.
Pen and paper out — try it before you reveal.
$109\% = 8300 \times 1.09$
€$9047$
€$9047$

That’s Percentages.

A percentage of an amount, and increases with the unitary method — the foundation for all money questions.

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