Help with this problem.

Question

on Saturday, Maria drove 150 miles from her home to visit her parents. She drove at a constant speed. On Monday she drove the 150 miles back to her home and again drove at a constant speed. On Monday her drive took her 0.5 hours longer because her speed was 10 miles per hour slower. How many hours did she drive on Saturday?

Answer 1

                      Rate           *      time           = distance

Saturday          x                       150/x              150

Monday            x-10                  150/(x-10)      150    Note: time=distance/rate

 

150/(x-10)    -    150/x    = 0.5

 

Multiply bu common denominator to get

 

300x - 300(x-10) = x(x-10)

 

300x - 300x + 3000 = x² -10x

                       0     = x² -10x - 3000

                       0     = (x-60)(x+50)

                        x=60 or x=-50

 

Since a rate must be positive, x=60. Now plug it in to the table above and answer the question. Hope this helped