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?

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