Correct Answer - Option 1 : 12 min

**GIVEN: **

Ram walks at a speed of 10 km/h. Today the day was very hot so walked at 2/5^{th} of his average speed. He arrived at his school 18 minutes late.

**FORMULA USED:**

Time = Distance/Speed

**CALCULATION:**

Suppose the distance between his school and home = X km

Decreased speed = 10 × 2/5 = 4 kmph

According to the question:

X/4 - X/10 = 18/60 = 3/10

⇒ X = 2 km

So,

Usual time he takes to cover the distance between his school and home = 2/(10/60) = 12 min