> a wheelchair ramp has a slope of 1/10
means that it rises 1 foot (rise) over a horizontal distance (run) of 10 feet.
Slopes are measured by the ratio rise/run.
For example, a rampe of 1/17, which is ususally the maximum preferred slope to enable manual wheelchairs to climb, with a rise of 2 ft will need a horizontal distance of 2*17=34 ft.
I'm sure you can take it from here.