Question

Te: 11/05/2020

Time: due to 8h00
Assignment of Mathematics of year 10 class
1. Natasha invests £250 in a building society account. At the end of the year her account is credited with 2% interest. How much interest had her £250 earned in the year?

2. Alan invests £140 in an account that pays r% interest. After the first year he receives £4.20 interest. What is the value of r, the rate of interest?

3. What is the actual rate of interest if £4000 deposited for 3 years attracts interest of £1440?

4. I deposit £250 in a high-earning account paying 9% compound interest and leave it for three years. What will be the balance on the account at the end of that time?

5. You borrow £500 for four years and agree to pay 6 1 2 % compound interest for this period. What amount will you have to pay back?

Answer 1

Explanation:

1) P = £ 250

r =2%

t = 1

I = Prt

`=250*(2)/(100)*1\\`

Interest = £ 5

2) P = £140

I = £ 4.20

t = 1

`4.20=140*(r)/(100)*1\\\\(4.20*100)/(140)=r\\\\r = 3`

r =3 %

3) P = £ 4000

t = 3 years

I = £ 1440

`1440=4000*(r)/(100)*3\\\\1440*(100)/(4000*3)=r\\\\r=12`

r = 12%

4) Amount=p*[1+(r/100)]^t

`=250*(1+(9)/(100))^(3)\\\\=250*((109)/(100))^(3)\\\\=250*(1.09)^(3)\\\\`

= £323.76