SOLUTION: A student begins to walk along a straight road at the rate of 3 km/h to the next town which is 18 km away. After 10 minutes a car picks him up and in 15 more minutes he is in town.

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: A student begins to walk along a straight road at the rate of 3 km/h to the next town which is 18 km away. After 10 minutes a car picks him up and in 15 more minutes he is in town.      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 279456: A student begins to walk along a straight road at the rate of 3 km/h to the next town which is 18 km away. After 10 minutes a car picks him up and in 15 more minutes he is in town. How fast was the car traveling?
(the time is in minutes which throws me for a loop)
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A student begins to walk along a straight road at the rate of 3 km/h to the next
town which is 18 km away.
After 10 minutes a car picks him up and in 15 more minutes he is in town.
How fast was the car traveling?
:
Let's put all the times in hrs and see what we have
10/60 = 1%2F6 hr
:
15/60 = 1%2F4 hr
:
Let s = the speed the car is traveling
:
Write a dist equation: dist = speed * time
:
Walk dist + ride dist = 18 km
3*1%2F6 + 1%2F4s = 18
3 cancels into six so we have
1%2F2 + 1%2F4s = 18
Multiply by 4 to get rid of the denominators; results:
2 + s = 4(18)
:
s = 72 - 2
s = 70 km/hr is the speed of the car
;
;
Check solution by finding the total dist
3*1%2F6 + 1%2F4(70) =
.5 + 17.5 = 18
:
:
Did this straighten things out for you?