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Next scheduled challenge Saturday — AP Calculus AB Oct 10, 2026
👁 12 views on this week’s challenge
GAT / Qudurat Quantitative Oct 7, 2026 Hard Geometry Using side ratio and perimeter to find area ≈ 105 sec

Rectangle Perimeter with Ratio

The length and width of a rectangle are in the ratio 5:3. If the perimeter is 64, what is the area of the rectangle?

Choose your answer:

Need a hint?

Let the length be 5k and the width be 3k.

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Correct answer

C. 240

Solution

Let:

Length = 5k

Width = 3k

The perimeter is:

2(5k + 3k) = 64

2(8k) = 64

16k = 64

k = 4

So:

Length = 20

Width = 12

Area:

20 × 12 = 240

Detailed solution

The perimeter gives the sum of length and width indirectly. Since 2(L + W) = 64, the value L + W is 32. The ratio parts 5k + 3k equal 32, giving k = 4.

Common mistake

A common mistake is treating 64 as L + W instead of the full perimeter.

Trap logic

The trap is forgetting to divide the perimeter by 2.

What this reveals

If this was missed, the issue may be formula setup, not area calculation.

StudyGlitch notes

GAT geometry questions often combine ratio and shape formulas.

For rectangle ratio problems, translate the ratio into variables, then use the perimeter formula carefully.

Remember: perimeter of rectangle is 2L + 2W, not L + W.

This week’s question is more than a score.

A wrong answer usually points to a pattern: slow recognition, a trap choice, weak setup, or pressure under time. Use this challenge as a signal, then connect it to your diagnostic, practice history, and weekly StudyGlitch progress.