Question

The sale of sweets during last week was less by 20%. How much percent is this week’s sale of sweets more than that of last week?

Answer 1

Hint: Assume this week’s sale to be 100 and then proceed with the conditions given in the question.

Complete step-by-step answer:
Let the sale of sweets in this week be 100 of them.
Therefore, the sale during last week was less by 20%
First let us calculate 20% of 100
$\dfrac{{20 \times 100}}{{100}} = 20$
As last week’s sale is less than 20% i.e. 20, we subtract it from 100.
Therefore, last week’ sale = $100 - 20 = 80$ sweets
Now we have to calculate how much this week’s sweet sale is more than that of last week.
Last week’s sale was 80 sweets and this week’s sale was 100 sweets.
So, this week’s sale is more than that of last week by $100 - 80 = 20$ sweets.
Now, as we are comparing this increase in number of sweets from last week the percentage increase will be
$
   = \dfrac{{(100 - 80)}}{{80}} \times 100 \\
   = 25\% \\
$

Thus, this week’s sale is more than last week by 25%.

Note: We can also solve this sum by algebra. If we take the sale of sweets for this week to be some variable, let’s suppose $x$ we can also proceed in that manner. This approach would be good when the number of conditions in the question are more. If there are a few conditions then we can assume some quantity, most likely 100 and proceed.