Question

How do you calculate the percentage change of $64$ to $80$?

Answer 1

Hint: To solve the given problem we need to use the formula that helps to find the percentage change by replacing the given values and the formula is Percentage change $=\dfrac{new-old}{\left| old \right|}\times 100\%$. Here we have to substitute the given number as 80 and 64 for new and old numbers respectively and then we can find the percentage change between the given numbers.

Complete step by step solution:
Now according to this problem,
Here the value for new is $80$ and the value for old is given by $64$.
We have the formula to calculate the Percentage change as below,
Percentage change $=\dfrac{new-old}{\left| old \right|}\times 100\%$
Applying this value in the above equation we get,
$\Rightarrow \dfrac{80-64}{\left| 64 \right|}\times 100\%$
We can calculate 80 - 64 to substitute in further step as below,
$\Rightarrow \dfrac{16}{64}\times 100=25\%$ (Increase)
Here, there are twenty-five percentage increases in the value from 64 to 80 in the given problem.

Note: The problem can be solved by the above solved method, in this method we do use a formula to calculate the raise in the percentage and in this problem the older value is $64$ and new value is $80$, here in this case the percentage is increasing because newer value is greater than older value, one should be careful in determining the older value and the newer value. Otherwise, one may fail in determining whether the percentage is increasing or decreasing in the given problem.