Aman travelled at a speed of 20 m/min for 100 min, and at a speed of 70 m/min for 50 min. His average speed is:

Speed 1 = 20 m/min, Time 1 = 100 min

Speed 2 = 70 m/min, Time 2 = 50 min

Distance = Speed × Time

Average Speed = $$\frac{\text{Total Distance}}{\text{Total Time}}$$​​

Distance 1 = 20 × 100 = 2000 m

Distance 2 = 70 × 50 = 3500 m

Total Distance = 2000 + 3500 = 5500 m

Total Time = 100 + 50 = 150 min

Now,

Average Speed = $$\frac{5500}{150} = \bf \frac{110}{3}\, m/min.$$​​