posted by Becky .
Ella walked 4.5 km/h to her friends house. She walked back home from her friends house at 3.5 km/h. She walked a total of 40 minutes. How many minutes was her walk on her way to her friends house?
(4.5 km/hr x X) + (3.5 km/hr x Y) = 40
Where X is the time there and Y is your time back.
X = (40 - 3.5 Y) / 4.5
= 8.88 - 0.77Y
Now plug X back into your original eqn and solve for Y:
4.5 (8.88 - 0.77Y) + 3.5Y = 40