Question

If a boy walks from his house at $4$ km/hr he reaches school $10$ min early, if he walks at $3$ km/hr he reaches 10 min late. What is the distance from his house to school ?

• A. $6$ km
• B. $4.5$ km
• C. $5$ km
• D. $4$ km

Answer 1

The correct option is D $4$ km

Let the distance be $x$ km

Difference in timing$=20$ min$=\frac{1}{3}$ hr

$\therefore \frac{x}{3}-\frac{x}{4}=\frac{1}{3}$

$\Rightarrow 4x-3x=4$

$\Rightarrow x=4$ km