posted by johnny on .
A family drove 1080 miles to their vacation lodge. Because of increased traffic density, their average speed on the return trip was decreased by 6 miles per hour and the trip took 2.5 hours longer. Determine their average speed on the way to the lodge.
Can someone help define a variable and write an equation?
Sure, we can help with that.
Let V be the average speed GOING to the ladge, a distnce d = 1080 miles away.
V * T = 1080
(V-6)*(T+2.5) = 1080
Substitute 1080/V for T in the second equation and solve for V.