Question

13. A girl walks 12 km at the speed of 3 km/h. What change should she make in her speed to take (1) an hour less and (i) an hour more to cover the distance?​

Answer 1

According to the question,

Distance = 12km/hr

Speed = 3km/hr

So, time = $\frac{distance}{speed}$ = $\frac{12}{3}$ = 4 hours.

1) To change the time to an hour less, i.e, 3 hours,

speed = $\frac{distance}{time}$ = $\frac{12}{3}$ = 4km/hr

2)  To change the time to an hour more, i.e, 5 hours,

speed = $\frac{distance}{time}$ = $\frac{12}{5}$ = 2.4 km/hr