wondering where I went wrong...

[mathemalex]

Hello,
I am wondering where I went wrong with this problem: The commute to work is 56 miles one way.
The trip to work takes 10 minutes longer than the trip home. Your average speed to home is 8 mph
faster than to work. What is the avg speed on the trip home?

D = R * T

56 x + 8 56/(x+8)
56 x 56/(x)

56/(x+8) + 10 = 56/(x)

Thank you for your help!!

 

[Deleted member 4993]

Hello,
I am wondering where I went wrong with this problem: The commute to work is 56 miles one way.
The trip to work takes 10 minutes longer than the trip home. Your average speed to home is 8 mph
faster than to work. What is the avg speed on the trip home?

D = R * T

56 x + 8 56/(x+8)
56 x 56/(x)

56/(x+8) + 10 = 56/(x) -- your units are mixed up - hours and minutes are mixed here

Thank you for your help!!

In these problems, before starting calculations, one thing you must do is to define your variables.

What is x? - you don't tell!!

Let average speed way home = S mph

"Your average speed to home is 8 mph faster than to work"

average speed way work = (S - 8) mph

Time to go to work = 56/(S-8) hours

Time to come home = 56/S hours

"The trip to work takes 10 minutes longer than the trip home"

10 minute = 1/6 hours

Then the equation to solve:

56/(S-8) = 56/S + 1/6

Now solve for "S"