Question

Amar drives his car for 2 hours at a speed of 70 km/h, for 3 hours at a speed of 80 km/h and for 1 hour at a speed of 40 km/h and reaches his hometown. What is his average speed (in km/h)?

• A. 64
• B. 66
• C. 70
• D. 58

Answer 1

Answer:

C. 70

Distance traveled at a speed of 70 km/h = (2 × 70) km = 140 km Distance traveled at a speed of 80 km/h = (3 × 80) km = 240 km Distance traveled at a speed of 40 km/h = (1 × 40) km = 40 km Total time = (2 + 3 + 1) hours = 6 hours Total distance = 140 + 240 + 40= 420 km The average speed = 420/6 = 70 km/h