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1 . If a rectangle's length and width are both doubled, by what percent is the rectangle's area increased?

A. 50%
B. 100%
C. 200%
D. 300%

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Answer: Option D

Explanation:

Let, length and width of the rectangle are a and b respectively.
initial area = ab
Now rectangle’s length and breath are both doubled,
New length =2a
New width =2b
so, Area of new rectangle = (2a) × (2b) = 4ab
Increase in Area = 4ab - ab = 3ab
therefore,Percentage increase in area = 3ab/ab × 100 = 300 %

2 . If a rectangle's length and width are both doubled, by what percent is the rectangle's area increased?

A. 50%
B. 100%
C. 200%
D. 300%

View Answer

Discuss in Forum

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Report

Answer: Option D

Explanation:

Let the initial length and width be L and W respectively.

Initial area = L×W

New length = 2L

New width = 2W

New area = 2L×2W = 4 L×W

Increase in area = (4 L×W - L×W) / (L×W) × 100% = 300%

বাংলাদেশ ব্যাংক || অফিসার (ক্যাশ) (21-07-2023)

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