SOLUTION: Hi, I am completely lost. I need help with these please. 1) During the first part of a trip, a canoeist travels 63 miles at a certain speed. The canoeist travels 7 miles on the

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Hi, I am completely lost. I need help with these please. 1) During the first part of a trip, a canoeist travels 63 miles at a certain speed. The canoeist travels 7 miles on the      Log On


   

Question 603423: Hi,
I am completely lost. I need help with these please.
1) During the first part of a trip, a canoeist travels 63 miles at a certain speed. The canoeist travels 7 miles on the second part of the trip at a speed of 5 mph slower. The total time of the trip is 5 hours. What was the speed on each part of the trip?
2) Write a quadratic equation having the given numbers as solutions -3, -1
Thanks so much
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

 D = r*t or r = D/t

Let r and (r-5) represent speeds for 1st and 22nd parts of the trip respectivley

  63/r + 7/(r-5)= 5hrs |Multiplying thru by r(r-5)so as all denominators = 1

 63(r-5) + 7r = 5r(r-5)

  5r^2 -95r + 315 = 0

r+=+%2895+%2B-+sqrt%28+2725%29%29%2F%2810%29+

r = 14.72  or r =  4.28(can't use, throw out)

r = 14.72mph for the 1st part and 9.72mph for the 2nd part



a quadratic equation having the given numbers as solutions -3, -1 

f(x) = a(x+3)(x+1) |a=1  then x^2+4x+3 would be one such EQ