Two boys start running at the same time in the same direction at a speed of 10…

Step-by-Step Solution

To find the time when two moving objects will be a certain distance apart when moving in the same direction, we use the concept of relative speed.

1. Calculate the relative speed:

   • When two objects move in the same direction, their relative speed is the difference between their individual speeds.

   • Speed of Boy 1 = 10 km/hr

   • Speed of Boy 2 = 12 km/hr

   • Relative Speed = 12 km/hr - 10 km/hr = 2 km/hr.

   • This means that for every hour they run, the faster boy gains 2 km on the slower boy.

2. Calculate the time:

   • We want to find the time when they are 8 km apart.

   • Time = Distance / Relative Speed

   • Time = 8 km / 2 km/hr = 4 hours.