Question

on the first of january 2014, carol invested some money in a bank account. The account pays 2.5% interest per year. On the first of january 2015 carol withdrew £1000 from the account. On the first of january 2016, she had £23517.60 in the account. Work out how much carol originally invested in the account

Answer 1

Answer: £23,360

Explanation:

You can use algebra to solve this.

Assume that the original investment is x.

In the beginning of 2015 the balance had increased by 2.5% which is denoted as:

= 1.025x

Carol then withdrew a thousand:

= 1.025x - 1,000

This value then increased by 2.5% again by the beginning of 2016:

= 1.025 * (1.025x - 1,000)

Relevant expression therefore is:

1.025 *(1.025x - 1,000) = 23,517.60

1.025x - 1,000 = 23,517.60/1.025

1.025x = ‭22,944‬ + 1,000

x = 23,944/1.025

x = £23,360