Business Maths - Percentages

Year 11

Things you might remember

%•What digits can you see?•What math symbol can you see?

•Words that have cent in them?

Assumed concepts and skills

Expressing Fractions and Decimals as a % % of…. Quantities as a % of another Finding 100%

Percentage change

Text referecne

Chapter 6 Section 6.1 Page 201

% Δ - Discounts

In general, if r% discount is applied:

Discount = r × original price

100

New price = original price − discount

= (100 − r ) × original price

100

% Δ - Increases

In general, if r% increase is applied:

Discount = r × original price

100

New price = original price + increase

= (100 + r ) × original price

100

Increase - $20 CD increases by 10 %

Increase = 10% of $20

= 1/10 x 20 = $2

New cost =

original + increase

= $20 + $ 2 = $22

New Cost =

(100 + r ) × original price

100

(100 + 10) × $20

100

=(110) × $20

100

=$22

Percentage discount/Increase

Percentage discount = discount × 100 %

original price 1

Percentage increase = increase × 100 %

original price 1

An example – 5a

Nike trainers have $32 off with an original price of $249. What is the % dicount

Percentage discount = discount × 100 % original price 1

= 32 × 100 % 249

= 12.85%

Your turn

Chapter 6 Page 212 Qu1 a, d, f, h Qu2 a, d, g Qu3 b, c, f, g Qu4 a, d, e, g Qu5 c, d, e, g

Original Price

When r% discount has been applied: Original price = new price × 100

(100 − r ) When r% increase has been applied:

Original price = new price × 100

(100 + r )

Your turn

Qu6 a,b,d Qu7 B, c, d

Qu8 Qu9