need help on Algebra word problem

[staciebren]

A women drove part of a 185 mi trip at 50mi/h and the rest at 55mi/h. Find the distance she traveled at 50 mi/h if her total driving time was 3 h and 30 min.

How would you set up that problem?

 

[Deleted member 4993]

A women drove part of a 185 mi trip at 50mi/h and the rest at 55mi/h. Find the distance she traveled at 50 mi/h if her total driving time was 3 h and 30 min.

How would you set up that problem?

Another similar problem

John drove part of a 260km trip at 80 km/h and the rest at 100km/h.
Find the distance he travelled at 80 km/h if is total driving time was 3h.


Suppose

distance traveled at 80 kmph = d km

distance traveled at 100 kmph = (260 - d) km

time traveled at 80 kmph = d/80 hrs

time traveled at 100 kmph = (260-d)/100 hrs

Above equation can be solved easily...


If you still have problem - show your work and tell us exactly where you are stuck?

 

[Loren]

I would draw a sketch. It would be a line segment representing the total distance of 185 miles. Then I would pick a point on the line (NOT the midpoint) that represents the point at which she changed from one speed to the other.

Start_____________._____________________End

I know that d=rt where d is the distance, r is the rate and t is the time.

Based on the information given I can label the parts as follows:

Start_____________._____________________End
..................d.............................185-d

Using the d=rt formula, for the first part of the journey we have d=50t.
For the second part of the journey we have 185-d=55(3.5-t)
Now I would solve these two equations simultaneously for t which is the time it took for the first part of the trip. Once I have t, I would plug back into the first equation to get 75 miles which is the distance traveled at 50 mph.