Answer:
the amount of alcohol to be added is 128 grams
Explanation:
Given that:
The initial mass of the hand sanitizer = 480 grams
The initial strength of the hand sanitizer = 24 %
The new strength of the hand sanitizer = 40%
The objective here is to determine the final amount of alcohol that is to be added to get the new strength of the alcohol
First; let's find the mass of alcohol in the initial hand sanitizer;
SO;
= 24 % of 480

= 115.2 grams
If y should represent the mass of the alcohol added to have 40%; we have
The new amount of the alcohol to be

The new amount of the hand sanitizer will be

∴
For the new strength of sanitizer:
40 % of (480 + y) = (115.2 + y)

Thus ; we can conclude that the amount of alcohol to be added is 128 grams