Question

Greg drove to school at 30 mph to drop off his friend’s car. He then jogged home at 6 mph. If the entire trip too k him 1 hour, how far does he live from school?

Answer 1

5 miles

using the formula

time =
`(distance(d))/(speed)`, then his distance can be calculated

`(d)/(30)` +
`(d)/(6)` = 1

`(d)/(30)` +
`(5d)/(30)` = 1

`(6d)/(30)` = 1 ( multiply both sides by 30 )

6d = 30 ( divide both sides by 6 )

d = 5

He lives 5 miles from school

Answer 2

Answer: He lives 5 miles from school.

Solution:

Let distance between school and home be x miles.

Grey drove to school at speed = 30 mph

Distance between school and home = x mile

Formula used:
`Time=(Distance)/(Speed)`

Time taken by Grey from home to school
`T_1=(x)/(30)`

Grey jogged to home at speed = 6 mph

Distance between school and home = x mile

Formula used:
`Time=(Distance)/(Speed)`

Time taken by Grey from home to school
`T_2=(x)/(6)`

Grey took 1 hour for entire trip.

Therefore,
`T_1+T_2=1`

`(x)/(30)+ (x)/(6)=1`

`(x)/(30)+ (5x)/(30)=1`

`(6x)/(30)=1`

we get , x=5 miles.

He lives 5 miles from school.