Question

What is the percent change of 20 to 40?

Answer 1

Hint: We are given a question to find the percentage change (either increase or decrease) from 20 to 40. We can tell for sure that there is an increase. We will begin by finding the change or in other words, the increase, by subtracting the original number from the new number. And so we get the increase as, \[40-20=20\]. Now, we will divide the increase by the original number and the answer will be multiplied to 100 to get the percent increase. Hence, we will have the required percent increase.

Complete step-by-step solution:
According to the given question, we are asked to find the percent change from 20 to 40.
Here, 20 is the original number and the new number is 40. We can clearly see that there is an increase in the numbers.
So, we will first find by how much did the number 20 increase and for this we will simply subtract the original number from the new number, we get,
\[Increase=40-20=20\]
Next, we have to find the percentage increase when the number 20 got increased to 40, we have,
\[\%increase=\dfrac{Increase}{Original\_No.}\times 100\]
We will now substitute the known values in the above equation and we get the new expression as,
\[\Rightarrow \%increase=\dfrac{20}{20}\times 100\]
Solving the above expression, we get the value as,
\[\Rightarrow \%increase=100\%\]
Therefore, there is a hundred percent increase from 20 to 40.

Note: The above question can also be solved by first dividing the new number by the original number and then multiplying the answer by 100. We will then subtract the obtained percent by 100 and we will have the required percent, that is,
\[\dfrac{New\_No.}{Original\_No.}\]
\[\Rightarrow \dfrac{40}{20}=2\]
Converting to percent, we get,
\[2\times 100=200\%\]
\[\%increase=200\%-100\%=100\%\]
Therefore, there is a hundred percent increase from 20 to 40.