There is a sale on at a clothes shop. All shorts are reduced by 10% and all jeans are reduced by 20%.
The ratio of the original price of jeans to the original price of shorts is 7:5.
The sale price of the shorts is £18.
What is the sale price of the jeans?
[4 marks]

£22.40

Step-by-step explanation:

shorts: 10% off

jeans: 20% off

before discount:

jeans : shorts = 7:5

after discount:

shorts: £18

original price of shorts: £18/0.9 = £20

original price of jeans: j

j/20 = 7/5

5j = 7 × 20

j = 7 × 4

j = 28

original price of jeans: £28

sale price of jeans: £28 × 0.8 = £22.40

   £22.40

Explanation:

The sale price of the shorts is £18

Let's say x is the original price of the shorts.

If there's a 10% discount, then you pay the remaining 90%

sale price = 90% of x = 0.90x

Set this equal to the 18 pounds and solve for x.

0.90x = 18

x = 18/0.90

x = 20

The shorts originally were £20.

The discount saves you 2 pounds.

Let y be the original price of the jeans before the discount.

The price ratio of jeans to shorts is 7:5. This is before the discount for both items.

So,

(jeans price)/(shorts price) = 7/5

y/20 = 7/5

5y = 20*7

5y = 140

y = 140/5

y = 28

The jeans were originally £28 before the discount.

Now apply the 20% price reduction for the jeans.

20% of 28 = 0.20*28 = 5.60

You save £5.60 and the sale price of the jeans is 28-5.60 = 22.40 pounds.

Or you can use this shortcut

80% of 28 = 0.80*28 = 22.40

This shortcut works because if you save 20%, then you pay the remaining 80%

do you mean add both of the equations together

because if you do the answer is 10x-5

step-by-step explanation: