using quadratic formula...
A car traveled 60 miles at a certain speed. Then is traveled 50 miles at a speed 10 MPH less. If the total time for the trip was 2 hours what was the speed of the first part of the trip?

Question

using quadratic formula...
A car traveled 60 miles at a certain speed. Then is traveled 50 miles at a speed 10 MPH less. If the total time for the trip was 2 hours what was the speed of the first part of the trip?

anonymous · Answer

how do you write the equation?

ddcamp · Answer

For each part of the trip,
$$time = \frac{distance}{speed}$$
You know the distance and speed for the second part.

I don't think this actually needs the quadratic formula though.

anonymous · Answer

ok will try. the problem is that the teacher wants him using quadratic formula, that is the section they are on

ddcamp · Answer

Hmm...
Just realized I misread the problem :P sorry.

anonymous · Answer

was about to ask.... :)

ddcamp · Answer

Try setting it up something like:
$$2 hours = \frac{60 miles}{x\ mph} + \frac{50miles}{x-1\ mph}$$

ddcamp · Answer

Where x is the speed on the first part of the trip.

anonymous · Answer

bottom of the 50 mile side... should that be x-10MPH?

ddcamp · Answer

Yeah...

ddcamp · Answer

I should probably get some rest before trying to help anyone else.

anonymous · Answer

we had that equation at one point but failed to get the answer

ddcamp · Answer

Try multiplying both sides of the equation by (x-10) and x, to get rid of the denominators. Then, combine like terms.

anonymous · Answer

so $$60(x-10)+50x=2x(x-10)$$

anonymous · Answer

we got 60
can anyone check for me?