Question

If Ying Zyiyu covers the first 200 miles of a trip going at 50 mph and the last hundred going 40 mph, what was his average speed for the entire trip?

Answer 1

the person covers different distances at different speeds

to find the average speed we have to find the total distance travelled and the total time taken

average speed = total distance travelled / total time taken

first 200 miles

speed - 50 mph

time taken for 50 miles - 1 hour

then time for 200 miles - 1/50 x 200 = 4 hours

last 100 miles

speed - 40 mph

time taken for 40 miles - 1 hour

time for 100 miles - 1/40 x 100 = 2.5 hours

total time taken for a distance of 300 miles - 2.5 + 4 = 6.5 hours

average speed = 300 miles / 6.5 hours = 46.2 mph

average speed is 46.2 mph