Question

Karla will walk her bike at a speed of 6 mile/hour from her house to the bike

shop, which is 2.5 mi from her house, to get the bike fixed. She expects to
wait 30 min for the repair. Then she will return home by riding her bike at a
speed of 15 miles/hour. How long will the entire trip last? *
A. 1.30 hours
B. 1.50 hours
C. 0.50 hour
D. 1.08 hours

Answer 1

D. 1.08 hours

Explanation:

Speed = distance / time

Going to the bike shop

speed = 6 mile/hour

Distance = 2.5 mi

Time = t

Speed = distance / time

6 = 2.5 / t

Cross product

6t = 2.5

Divide both sides by 6

t = 2.5/6

= 0.417 hour

She waited for 30 minutes for the repair, that is 0.5 hour

Going back home

Speed = 15 miles/hour

Distance = 2.5 mi

Time = t

Speed = distance / time

15 = 2.5 / t

Cross product

15t = 2.5

Divide both sides by 15

t = 2.5 / 15

= 0.167 hour

Total time of the entire trip =

0.417 hour + 0.5 hour + 0.167 hour

= 1.084 hour

Approximately 1.08 hour

The correct answer is D. 1.08 hours