algebra word problem: still stuck
posted by john .
question:
rachel allows herself 1 hour to reach a sales appt 50 miles away. after she has driven 30 miles, she realizes that she must increase her speed by 15mph in order to get there on time. what was her speed for the first 30 miles?
Responses
* college algebra word problem  Reiny, Tuesday, February 17, 2009 at 9:09am
let her speed for the first leg be x mph
let her speed for the second leg be x+15 mph
so her time for the first leg is 30/x
her time for the second leg is 20/(x+15)
but 30/x + 20/(x+15) = 1
multiplying both sides by x(x+15) and simplifying I got
x^2 + 35x  450 = 0
(x+10)(x45) = 0
x = 10, which is silly or
x = 45 mph
* college algebra word problem  john, Tuesday, February 17, 2009 at 4:04pm
But wouldnt that actually factor into
(x10)(x+45)
which would imply that the positive value for x is actually 10.
plugging that back into the problem, that means she can go 30 miles at 10 miles per hour and 20 miles at 25 miles per hour to arrive at 50 miles in an hour?
how can she go 30 miles at 10 miles per hour? the speed doesnt seem correct here.
* college algebra word problem....help  john, Tuesday, February 17, 2009 at 4:28pm
Is it possible that the equation should have been set up as:
30miles(xmiles/per 1 hour) + 20miles (x+15/per 1 hour) = ?
Im stuck

What were out of pocket expenses for elderly person in poor health when in a certain year his out of pocket expenses were $3335. More than someone in good health whose out of pocket expenses were $6667.
Respond to this Question
Similar Questions

Math
A small truck is to be driven 300 miles on a freeway at a constant speed of x miles per hour. Speed laws on the freeway require that a truck must be driven between 30 miles per hour and 70 miles per hour. assume that fuel cost $3.50 … 
algebra
rachel allows herself one hour to reach a sales appointment 50 miles away. after she has driven 30 miles, she realizes that she must increase her speed by 15mph in order to arrive on time. what was her speed for the first 30 miles? 
college algebra word problem
rachel allows herself 1 hour to reach a sales appt 50 miles away. after she has driven 30 miles, she realizes that she must increase her speed by 15mph in order to get there on time. what was her speed for the first 30 miles? 
math....please help!
rachel allows herself 1 hour to reach a sales appt 50 miles away. after she has driven 30 miles, she realizes that she must increase her speed by 15mph in order to get there on time. what was her speed for the first 30 miles? 
algebra
Rachel allows herself 1 hour to reach a sale appointment 50 mile s away. After she has driven 30 miles, she realizes that she must increase her speed by 15 miles per hour in order to get there on time. What was her speed for the first … 
Algebra 2
A cars fuel efficiency is 24 miles per gallon and can be driven 324 miles with a full tank of gas. Write an expression for the amount of miles that be driven after X gallons have been used. 
Math Word Problem
Steve's boat will go 14 miles per hour in still water. If he can go 13 miles downstream in the same amount of time as it takes to go 10 miles upstream, then what is the speed of the current? 
Math Multistep word problems
A canoe in still water travels at a rate of 10 miles per hour. The current today is traveling at a rate of 3 miles per hour. If it took an extra hour to travel upstream, how far was the trip one way? 
Math
Suppose you are driving to visit a friend who lives far away. You are driving at an average rate of 55 miles per hour. You must drive a total of 295 miles. If you have already driven 20 miles, how long will it take you to reach your … 
6th grade math
Suppose you are driving to visit a friend in another state. You are driving 60 miles per hour. You must drive 480 miles total. If you have already driven 120 miles, how long will it take you to reach your destination?