Answer: 48.5%
Step-by-step explanation:
The quantity 50.5 incresed to 75. The change in value is:

The change was 24.5, so we need to find what percentage of 50.5 is 24.5.
For this we can use the rule of three.
Quantity Percentage
50.5 ---> 100%
24.5 ---> x
this means that if 50.5 is the 100%, 24.5 is a percentage x. This percentage x is found using the rule of three by multiplying que cross quantities in the last table (24.5 by 100), and then dividing by the remaining amount (50.5).
Thus:

The percentage change between 50.5 and 75 is 48.5%