Question: The percentage increase in the area of a rectangle, if each of its sides is increased by 20% is:
[A].40%
42%
44%
46%
[A].
[B].
[C].
[D].
Answer: Option C
Explanation:
Let original length = x metres and original breadth = y metres.
Original area = (xy) m2.
| New length = | 120 | x | m | = | 6 | x | m. | ||
| 100 | 5 |
| New breadth = | 120 | y | m | = | 6 | y | m. | ||
| 100 | 5 |
| New Area = | 6 | x x | 6 | y | m2 | = | 36 | xy | m2. | ||
| 5 | 5 | 25 |
The difference between the original area = xy and new-area 36/25 xy is
= (36/25)xy – xy
= xy(36/25 – 1)
= xy(11/25) or (11/25)xy
| Increase % = | 11 | xy x | 1 | x 100 | % | = 44%. | |
| 25 | xy |
Video Explanation: https://youtu.be/I3jLjLPn1W4