SOLUTION: hey i need help on this one here would really appreciate it... Harriet drove for 90 miles in the city. when she got on the highway she increased her speed by 20 mph and drove fo

Question 682925: hey i need help on this one here would really appreciate it...
Harriet drove for 90 miles in the city. when she got on the highway she increased her speed by 20 mph and drove for 130 miles. If Harriet drove for a total of 4 hours, how fast did she drive on the highway?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = her speed in mi/hr in the city
= her speed in mi/hr on the highway
Let = time in hrs she drove in the city
= time in hrs she drove on the highway
---------------
Harriet's equation for the city:
(1)
Harriet's equation for the highway:
(2)
----------------------------
(1)
and
(2)
(2)
(2)
(2)
(2)
(2)
Use the quadratic formula

and, since = her speed on the highway,

She drove 65 mi/hr on the highway
check:
(2)
(2)
(2)
(2)
(2)
(2) hrs
and
(1)
(1)
(1) hrs
OK

RELATED QUESTIONS
Please help me! I've been stuck on this problem for a while now and could really use some (answered by MathLover1,reviewermath)

Hey, I am stuck on this question, and really need help...please help me! Jaime bought... (answered by rfer)

I need help on this distance problem; I am pretty sure that the formula is D1=K+D2 but I (answered by solver91311)

for h(x)=2x^2+6x-9 & k(x)=3x^2-8x+8 find h(x)-2k(x) I would really really... (answered by stanbon)

I need help finding the equation for this word problem. Meredith drove at an average... (answered by ankor@dixie-net.com)

Hello, I am struggling with this homework problem. I need to solve for "x" of course, but (answered by bucky)

Hey! My name is Lacey and my teacher gave me the opportunity for extra credit with a... (answered by checkley77,jim_thompson5910)

I do not need help on a specific problem; however, I would appreciate guidance on how to... (answered by lwsshak3)

Hey, I really need some help on this problem.. I just can't understand it. If you could... (answered by Earlsdon)