Need some with this question : when driving to their family reunion, river's mom drove 10 miles at a rate of x mph and then 25 miles at a rate of x + 10 mph . the total driving time was 45 minutes. what were the two driving speeds at which river's mom drove?

The speed of River's mom drove for 10 miles distance is 0.234 mph

The speed of  River's mom drove for 25 miles is 10.234 mph  

Step-by-step explanation:

Given as :

The first distance cover by River's mom = 10 miles

The rate of speed = x mph

The second distance cover by river's mom = 25 miles

The rate of speed = x + 10 mph

The total driving time = 45 min

Now, According to question

Time =

So, 45 = +  

Or, 9 = +  

Or, 9 × x × ( x + 10 ) = 2 × ( x + 10 ) + 5 x

Or, 9 x² + 90 x = 2 x + 20 + 5 x

Or, 9 x² + 90 x = 7 x + 20

Or, 9 x² + 90 x - 7 x - 20 = 0

Or, 9 x² + 83 x - 20 = 0

Solving this quadratic equation

x =

Or, x =

Or, x =

∴  x = , tex]\frac{-83-87.22}{18}[/tex]

I.e x = 0.234 , - 9.4567

We consider x = 0.234

So, The speed for 10 miles distance = x = 0.234 mph

and The speed of 25 miles = x + 10 = 0.234 + 10 = 10.234 mph

Hence The speed of River's mom drove for 10 miles distance is 0.234 mph

and The speed of  River's mom drove for 25 miles is 10.234 mph   Answer

1/4 because there is 4 grades.