Question

How do you calculate the percentage change of 24 to 21?

Answer 1

Hint: The change of number 24 to the number 21 we have to find the difference between the number first and then it should be divided by the number 21 and then we have to find the percentage value of the number obtained. We can also use the formula \[p=\dfrac{N-O}{O}\times 100\] to find the percentage change between any two numbers.

Complete step by step solution:
The formula for change in percentage between any two numbers is:
\[p=\dfrac{N-O}{O}\times 100\]
Here the terms are:
P is the percentage change
N is the new value: - 21 for this problem
O is the old value:-24 for this problem
Substituting and calculating gives:
\[p=\dfrac{21-24}{24}\times 100\]
\[p=-\dfrac{3}{24}\times 100\]
P = -12.5
The change can be positive or negative, but the percentage change should be represented without signs.
The change from 24 to 21 is obtained to be 12.5%.

Note: It is primarily important for us to remember the formula of finding the percentage change between two numbers; here they are 24 and 21. We can also solve this question even in case we don’t remember the formula just by using our common sense. The important point to be remembered here is to find the difference in percentage form as it is clearly mentioned in the question above. Students can also go wrong in representation of the percentage change by indicating the negative sign with the percentage value.