Question

A student rides a bicycle at 8 kms/hr and reaches the school 2.5 minutes late. The next day he increases the speed to 10 kms/hr and reaches school 5 minutes early. How far is the school from his house?

Options

• 4 kms

• 8 kms

• 5 kms

• 10 kms

Answer 1

5 kms

Explanation:

Let Distance be = D, Speed S₁ = 8 km/m, Speed S₂ = 10 km/m,

`"D"/"S"_1-"D"/"S"_2="T"_1-"T"_2` ..... `(∴"D"/"S" ="T")`

`"D"/8-"D"/10`=7.5 minutes or `7.5/60` m

`(5"D"-4"D")/40=75/600⇒5`

D = 5 km