In this question, it is given that
You start skiing at an elevation 240 ft from the base of the hill and your elevation decreases 8 ft each minute. Your friend starts skiing 320 ft from the base of the hill and her elevation decreases 12 ft per minute.
Let the elevation is represented by h and time by tminutes .
So we have two equations here, which are
And for same elevation, height is same. THat is
THerefore,after 20 minutes, they are at same elevation .