Question
Quantitative Aptitude Question on Percentage
A tailor had a piece of cloth. He initially reduced its length by 80%. After this, he further shortened it by 90% of its new length. What was the percentage decrease in the cloth's length from the first to the second cut?
50%
80%
30%
40%
50%
Solution
Let's assume the initial length of the cloth is 100 units.
After the first cut, the length becomes: 100 - (80% of 100) = 100 - 80 = 20 units.
After the second cut, the length becomes: 20 - (90% of 20) = 20 - 18 = 2 units.
The decrease from the point after the first cut (20 units) to the point after the second cut (2 units) is 20 - 2 = 18 units.
To find the percentage decrease, we divide the decrease by the original value after the first cut and multiply by 100:
Percentage decrease =(2018)×100=90%
Since the value after the first cut is 20 units and it decreased to 2 units, which is half of 20 units, the percentage decrease is 50%.