Finding a percentage increase or decrease
The percentage increase or decrease can be calculated this using the following formulae:
Finding a percentage increase
A baby Panda weighs 3.6 kg at birth. After 8 weeks the baby Panda’s weight has increased to 4.3 kg.
What is the baby’s percentage increase in weight?
The actual increase = 4.3 kg – 3.6 kg
= 0.7 kg
Finding a percentage decrease
If a shirt was previously $26 and where reduced to $18, was is the percentage decrease?
The actual decrease = $26 – $18 = £8
Finding a percentage profit
A shopkeeper buys fruit bars wholesale at a price of 30p per bar. He then sells the fruit bar in his shop at 48p each.
What is the percentage profit?
Finding a percentage loss
A bond dealer buys a number of bond at £3.66 each. After a week the price of the shares has dropped to £3.20.
What is the percentage loss?
Point to note:
- The number of bonds bought does not make a difference to the percentage loss as it is a proportion of the amount therefore it makes a different to her actual loss only.
- Always use the same units when working out the percentage profit/loss.