40 miles per hour what is that in feet per hour

40 miles per hour = 211,200 feet per hour.

211,200

There are 5280 Feet in 1 Mile

40×5280=211200

the 8 in 8,420 is in the thousands place so it's value is 8 thousand.

the 8 in 6,870 is in the hundreds place so it's value is 8 hundred.

divide 8000 by 800 to find the answer:

8000 / 800 = 10

the 8 in 8,420 is 10 times greater than the 8 in 6,870