Question

In reducing one's speed from 70 mph to 50 mph, how much of a percentage decrease in stopping distance is realized (to the nearest percent)?

Answer 1

we are given

we are given relation between speed and distance

distance ( when speed =70mph) is

=328feet

so,
`d_1=328`

distance ( when speed =50mph) is

=183feet

so,
`d_2=183`

now, we can find percentage in decrease

`=(d_1-d_2)/(d_1) * 100`

now, we can plug values

`=(328-183)/(328) * 100`

`=44`%...........Answer