posted by Brandon on .
Ella can drive 65 mi on side roads in the same time that it takes to drive 30 mi on the interstate. Ella's rate on the side roads is 7 mi faster than her rate on the interstate, what is her rate on the side roads?
Use the equation distance = rate multiplied by time (d = r*t).
Let s be her rate on the side roads.
d = r*t
65 = s*t
Now, form a similar equation (using the numbers 30 & 7).
After you come up with your two equations, use either substitution or elimination to solve it.