A train travels at a speed of 30 km÷hr for 12 minutes and at a speed of 45 km÷hr for the next 8 minutes. The average speed of the train for this journey is?
Note
Total distance travelled = [{30 ☓ (12 ÷ 60)} + {45 ☓ (8 ÷ 60)}]km = 12 km.
Total time taken = (12 + 8) min
= 20 min
= (1 ÷ 3) hr.
Average speed = (12 ☓ 3) km/hr = 36 km/hr.