Question 297628
60/60=1 mps
The escalator lifts at 1 meter per sec.
 
r*t=d
r=d/t=60/90=2/3 mps
The child goes at 2/3 mps
1+2/3=5/3 mps
together they go 5/3 meters per sec
5/3*x=60
x=60*3/5=12*3=36 seconds