Question

Martin rides to Cambridge 30 miles away from home at the average rate of 10 miles per hour. He return on the better road that is 50% longer where he can increase his rate by 100%. How much time does he save by taking the better road on his return trip?

a-2 1/4 mins
b-15 mins
c-45 mins
d-2 hrs 15 mins
e-2 hrs 45 mins

I suck at these kind of questions, help?

Answer 1

30 miles at 10 miles per hour

if you use
rate * time = distance
can you figure out how long it took to get to Cambridge ?

Answer 2

10?

Answer 3

replace rae with 10, time with T (unknown), and distance with 30
10 T = 30

to solve for T (in hours) divide both sides by 10
can you do that ?

Answer 4

Wait, no 3 hrs?

Answer 5

yes, 3 hours

now part two, returning

the road that is 50% longer than 30 miles
what is 50% of 30 ?

Answer 6

15.

Answer 7

so the road back is 15 longer than 30
how long is the road back ?

Answer 8

45...?

Answer 9

yes, so distance back is 45

increase his rate by 100%
his rate was 10 mph. if you increase by 100% you increase by 10
his rate going home is 10+10= 20 mph

rate * time= distance
20 * T= 45
how long does it take to get home (in hours) ?

Answer 10

20 * T= 45
to solve, divide both sides by 20

Answer 11

2 hrs and 15 minutes?

Answer 12

yes, 2 and a quarter hours

He took 3 hours to get there
and 2 hours 15 mins to get back

How much time does he save by taking the better road on his return trip?

Answer 13

45 mins