SOLUTION: Katrina drove her car to Boston at a speed of 100 kph (kilometers per hour). She drove back at 75 kph. The total driving time was 7 hours. How far away was Boston?

Question 256566: Katrina drove her car to Boston at a speed of 100 kph (kilometers per hour). She drove back at 75 kph. The total driving time was 7 hours. How far away was Boston?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Katrina drove her car to Boston at a speed of 100 kph (kilometers per hour).
She drove back at 75 kph. The total driving time was 7 hours.
How far away was Boston?
:
Let d = distance to Boston
:
Write a time equation: Time = dist/speed
:
To B. time + from B. time = 7 hrs
+ = 7
Multiply by 300 to get rid of the denominator, results
3d + 4d = 300(7)
7d = 2100
d =
d = 300 mi to B.
:
:
Check solution, find the time of each trip
300/100 = 3 hrs
300/75 = 4 hrs
---------------
total = 7 hrs
;
:
That's pretty easy, right?

RELATED QUESTIONS
Natasha drove from Bedington to Portsmouth at an average speed of 100 km/h. On the way... (answered by checkley77,nerdybill)

Natasha drove from Bedingfield to Portsmouth at an average speed of 100 km/h to attend a... (answered by josmiceli)

Dylan drove to the beach,which is one hundred thirty-six kilometers away,at forty-eight... (answered by checkley77)

A driver drove at 80 kph for 20 minutes of a one -hour trip. His average speed for the... (answered by srinivas.g,MathTherapy)

A person traveling 210 km by car drove the first part at 100 kph and the rest at 80 kph.... (answered by TimothyLamb,MathTherapy)

Caitlin drove from Greensville to Bluesburg at a speed of 50 mi/h. On the way back, she... (answered by josgarithmetic)

: A motor car travelled 3 consecutive kilometers, first kilometer at the speed of 35... (answered by Alan3354)

Angelina drove at an average rate of 80 kph and then stopped 20 minutes for gas. After... (answered by ankor@dixie-net.com)

Maria drove a total of 301.5 miles in two legs of a trip. In the first part of her... (answered by greenestamps)