Question

8 The cost of a laptop increased by 25% between

2015 and 2019
In 2019. the laptop cost £1000
How much did the laptop cost in 2015?

Answer 1

Given:

The cost of a laptop increased by 25% between 2015 and 2019.

In 2019, the laptop cost £1000.

To find:

The cost of the laptop in 2015.

Solution:

Let x be the cost of the laptop in 2015.

The cost of a laptop increased by 25% between 2015 and 2019. So, the cost of the laptop in 2019 is

Cost of laptop in 2019 =
`x+(25)/(100)x`

=
`x+0.25x`

=
`1.25x`

In 2019, the laptop cost £1000.

`1.25x=1000`

`x=(1000)/(1.25)`

`x=800`

Therefore, the cost of the laptop in 2015 is £800.