Question

Aman left his house at 10.00 am and reaches his school at 10.30 am at a constant speed. Next day, he wants to reach his school 10 min earlier. By how much percent he will definitely increase his speed.
1. 25%
2. 30%
3. 18%
4. 50%

Answer 1

Correct Answer - Option 4 : 50%

Given:

Time taken by Aman to reach his School = 30 min = 1/2 hr

Formula Used:

Distance = Speed × Time

Calculations:

Let, Distance of school from his house be D km

Speed of Aman = D/(1/2) = 2D km/h

Now, Expected time = 20 min = (1/3) h

Speed = D/(1/3) = 3D km/h

Increase in speed = (3D – 2D) = D km/h

Percentage increased = (D/2D) × 100 = 50%

∴ Speed must be increased by 50%