The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

Urgent! need help

On the 1st January 2014 Carol invested some money in a bank account.
The acount pays 2.5% compound interest per year.
On 1st january 2015 Carol withdrew £1000 from the account.
On 1st january 2016 she had £23 517.60 in the account.

Work out how much carol originally invested in the account.
Reply 1
Avatar for happily
happily
10
Original post by Amazejess2005
On the 1st January 2014 Carol invested some money in a bank account.
The acount pays 2.5% compound interest per year.
On 1st january 2015 Carol withdrew £1000 from the account.
On 1st january 2016 she had £23 517.60 in the account.

Work out how much carol originally invested in the account.


think of it as creating equations and finding missing value.
2014: Carol originally had £x
2015: Carol had 1.025x - 1000 pounds (£y) in her account after gaining interest and withdrawing £1000.
(let y = 1.025x-1000)
2016: Carol has £1.025y which is after getting her interest.
1.025y = 23517.60
so, y = 23517.60/1.025 = 22944
plug in that value into equation in 2015:
y = 1.025x-1000 = 22944
so, x = (22944+1000)/1.025 = 23360

Therefore, Carol originally had £23 360.00 in her account.
Thank youu

Original post by happily
think of it as creating equations and finding missing value.
2014: Carol originally had £x
2015: Carol had 1.025x - 1000 pounds (£y) in her account after gaining interest and withdrawing £1000.
(let y = 1.025x-1000)
2016: Carol has £1.025y which is after getting her interest.
1.025y = 23517.60
so, y = 23517.60/1.025 = 22944
plug in that value into equation in 2015:
y = 1.025x-1000 = 22944
so, x = (22944+1000)/1.025 = 23360

Therefore, Carol originally had £23 360.00 in her account.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you