Simple & Compound Interest, Growth & Decay (Edexcel GCSE Maths: Foundation)

Two samples of bacteria are prepared in a laboratory.

Sample A contains 100 bacteria.
The number of bacteria in the sample increase by 60% each hour.

Sample B contains 3000 bacteria.
The number of bacteria in the sample decreases at a rate of 19% per hour.

After 5 hours, which sample contains more bacteria.
You must show all your working.

Heather wants to invest £35 000 in a bank for 4 years.

Bank A  offers 3% compound interest.

Bank B offers 5.1% interest for the first year and 2.5% compound interest for the remaining 3 years.

Which bank will give Heather the most interest at the end of the 4 years.
You must show all your working.

$12000 is invested at a rate of n% per year simple interest.
At the end of 3 years the value of the investment is $12900.

Find the value of .

= ................................. 

Sonia wants to invest $5000 for 6 years.

Bank A pays compound interest at a rate of 3.5% per year.
Bank B increases the $5000 by 22% at the end of 6 years.

Which bank will give Sonia the most money at the end of 6 years and by how much?
You must show all your working.

Riya invests $30000 at a rate of 2.5% per year compound interest.

Calculate the value of her investment at the end of 7 years.
Give your answer correct to the nearest dollar.

$ ................................................. 

Six years ago a farmer invested $3750 at a rate of 4% per year compound interest.

The farmer grows carrots.
In 2018 the selling price for carrots was $96 per tonne.
In 2019 this selling price increased by 18%.

Work out the increase in the selling price from 2018 to 2019.

$ ..............................................

Paula invests $600 at a rate of% per year simple interest.
At the end of 10 years, the total interest earned is $90.

Find the value of

=........................................

$8400 is invested for 2 years at a rate of 3.5% per year compound interest.
Work out the total amount of interest earned by the end of the 2 years.

$.................................................... 

Harry invests $800 for 2 years at a rate of 3% per year compound interest.

Calculate the amount of interest he receives at the end of the 2 years.

$ ...........................

Tomas borrows $5000 for 3 years at a rate of 2.5% per year compound interest.
He pays back the whole amount, with interest, at the end of 3 years.

Calculate the total amount of money he pays back at the end of the 3 years.

$ .............................. 

A city has a population of 215 000 people.

The population of the city increases by 1.5% each year.

What is the population of the city after 3 years?

The value of a new TV is £850.
The value of the TV depreciates by 12% each year.

Work out the value of the TV after 2 years.

Trina invests $16000 at a rate of 5% per year compound interest.

Work out the value of her investment at the end of 4 years.

$.........................

Gino invests $6000 for 5 years at a rate of 1.2% per year compound interest.

Calculate the value of his investment at the end of the 5 years.
Give your answer correct to the nearest dollar.

$ .................................................

Lucia invests $5000 at a rate of 4.5% per year compound interest.

Calculate the value of her investment at the end of 7 years.

$ .................................................. 

Ella invests $4000 for 3 years at a rate of 1.2% per year compound interest.

Calculate the value of her investment at the end of the 3 years.

$...................................................

Javier invests $750 for 3 years at a rate of 1.8% per year compound interest.

Calculate the value of his investment at the end of the 3 years.

$ ................................................... 

Hawa invests $750 at a rate of 3.5% per year compound interest.

Calculate the value of his investment at the end of 3 years.

$ ..............................