On a journey across Dhaka, a bus averages 10 miles/h for 20% of the di

On a journey across Dhaka, a bus averages 10 miles/h for 20% of the distance, 30 miles/h for 60% of it and 20 miles/h for the remainder. What is the average speed for the whole journey? (A) 30 mph (B) 25 mph (C) 20 mph (D) 10 mph (E) 5 (…)