If a man moves up in an escalator to the top in one minute and he moves to the top by using stairs?

It will take only 15 seconds.

Way of solving.

Neet to build up three equations using the velocity equation " lv = t."
If the height is "h", Speed at occation 1 & 2 are S1 & S2 respectively.

Equation 1 --- 1 x s1 = h
Equation 2 -- 3 x s2 = h

Equation 3 -- time taken for reaching the top (Say "t") x(s1 + s2) = h

t = h/(s1 + s2) = h/ (h/1 + h/3) = 1/(1+4) = 0.25 minutes.