Question 8
Archie, Beatrice and Carlos walked up an upward escalator in 12, 10 and 6 steps respectively. Archie then ran down the escalator twice as fast as he walked up, taking 30 steps to reach the bottom. If the ratio of the time taken by Beatrice to that of Carlos to ascend the escalator is $m:n$, find $m+n$.
Editorial assumptions: each counted step covers one escalator tread; all walking/running speeds are relative to the escalator; the escalator speed is constant. Use positive coprime integers m and n. Without a lowest-terms convention, m+n is not unique.
Editorial assumptions: each counted step covers one escalator tread; all walking/running speeds are relative to the escalator; the escalator speed is constant. Use positive coprime integers m and n. Without a lowest-terms convention, m+n is not unique.