Question

A family is on a road trip. The speed limit during the first 145 miles of the trip is 60 mph, and the speed

limit during the last 190 miles is 65 mph. How many miles per hour over the speed limits must they drive in

order to arrive at their destination in 5 hours?

Answer 1

Answer:

first 145 mile 7mph

next 190miles 2mph

Step-by-step explanation:

total distance to be covered = 145+190=335miles

time = distance/speed

first 145 miles

time = 145/60 =2.41hr

next 190 miles

time = 190/65 = 2.92hr

Total time = 2.41+2.92 = 5.33hr

but we need to cover the entire distance in 5hr

Speed = distance /time

           =  335/5 = 67mph

That means in first 145 mile the speed over the speed limit will be 67-60= 7mph

similarly in the next 190miles speed over speed limit will be 65 - 67 = 2mph.