Question 80

Logical Reasoning Directions Easy

Instead of walking along two adjacent sides of a rectangular field, a boy took a short cut along the diagonal of the field and saved a distance equal to half the longer side. The ratio of the shorter side of the rectangle to the longer side is

(A) \( 1 / 2 \)
(B) \( 2 / 3 \)
(C) \( 1 / 4 \)
(D) \( 3 / 4 \)
View Dynamic Solution & Explanation
Correct Solution: Option D

Step-by-step Solution:

Quick Solution

This problem can be solved by setting up an algebraic equation based on the Pythagorean theorem and the information about the "distance saved".


1. Set Up the Equations

  • Let the longer side of the rectangle be l and the shorter side be s.
  • The distance when walking along the two adjacent sides is (l + s).
  • The shortcut distance along the diagonal is d. From the Pythagorean theorem, we know that d = √(l² + s²).
  • The "distance saved" is the difference between these two paths: (l + s) - d.

The problem states that this saved distance is equal to half the longer side. This gives us our main equation:

(l + s) - √(l² + s²) = l / 2


2. Solve for the Ratio (s/l)

- First, we rearrange the equation to isolate the square root term on one side:
l + s - l/2 = √(l² + s²)
l/2 + s = √(l² + s²)

- Next, we square both sides of the equation to eliminate the square root:
(l/2 + s)² = l² + s²
(l²/4) + (2 × l/2 × s) + s² = l² + s²
l²/4 + ls + s² = l² + s²

- The s² terms cancel out on both sides, leaving:
l²/4 + ls = l²

- Now, we solve for the relationship between l and s:
ls = l² - l²/4
ls = (3/4)l²

- Finally, to find the required ratio, we divide both sides by l²:
s/l = 3/4


Final Answer: The ratio of the shorter side of the rectangle to the longer side is 3/4.