At the start of 2014 Mikes car was worth £12000. the value of his car decreased 30% every year.
work out the value of the car at the start of 2017

The worth of car at the start of 2014 = $12000

The value of the car decreased 30% every year.

At start of 2015:

30% of 12000 = \frac{30}{100} \times 12000

100

30

×12000 = 3600

So, the value of the car at start of 2015 = 12000-3600 = $8400.

At start of 2016:

30% of 8400 = \frac{30}{100} \times

8400

100

30

×8400 = 2520

So, the value of the car at start of 2016 = 8400-2520 = $5880.

At start of 2017:

30% of 5880 = \frac{30}{100} \times

5880
100

30

×5880 = 1764

the value of the car at start of 2017 = 5880-1764 = $4116.

So, the value of his car at the start of 2017 is $4116.