The length of a rectangle is increased by 60%. By what percent would the width…

2019

The length of a rectangle is increased by 60%. By what percent would the width have to be decreased to maintain the same area?

  1. A.

    50%

  2. B.

    125%

  3. C.

    75.5%

  4. D.

    37.5%

Attempted by 1 students.

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Correct answer: D

Let the original length of the rectangle be L and width be W. Then, the original area is A = L × W.

When the length is increased by 60%, the new length becomes 1.6L.

Let the new width be W'. To maintain the same area, we have:

1.6L × W' = L × W

Dividing both sides by L: 1.6 × W' = W

So, W' = W / 1.6 = 0.625W

The decrease in width is:

W - 0.625W = 0.375W

Percentage decrease = (0.375W / W) × 100 = 37.5%

हिन्दी उत्तर:

मान लीजिए आयत की मूल लंबाई L और चौड़ाई W है। तब मूल क्षेत्रफल A = L × W है।

जब लंबाई में 60% की वृद्धि होती है, तो नई लंबाई 1.6L हो जाती है।

मान लीजिए नई चौड़ाई W' है। क्षेत्रफल को समान रखने के लिए, हमारे पास है:

1.6L × W' = L × W

दोनों तरफ L से भाग देने पर: 1.6 × W' = W

इसलिए, W' = W / 1.6 = 0.625W

चौड़ाई में कमी है:

W - 0.625W = 0.375W

प्रतिशत कमी = (0.375W / W) × 100 = 37.5%

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