A person walk up a stalled escalator in 90sec.when standing on the same escalator now moving,he is carried in 60 sec.the time he would take to walk up the moving escalator will be.

30 secs

Actually, its 36 secs

To solve this problem, we need to determine the time it would take for the person to walk up the moving escalator.

Let's assume that the length of the escalator is L, and the speed of the escalator is E.

When the escalator is stalled, the person walks up the escalator in 90 seconds. We can use the formula: time = distance / speed, to find the relative speed between the person and the escalator.

The relative speed of the person walking up the stalled escalator is L/90.

When the escalator is moving, the person is carried up the escalator in 60 seconds. We can again use the formula: time = distance / speed, to find the relative speed between the person and the moving escalator.

The relative speed of the person being carried up the moving escalator is L/60 - E.

To find the time it would take for the person to walk up the moving escalator, we need to determine the relative speed between the person and the escalator. This can be calculated by subtracting the speed of the escalator from the relative speed when the escalator is moving.

Relative speed between the person and the escalator when the escalator is moving = L/60 - E.

Now, let's use the formula: time = distance / speed to find the time it would take for the person to walk up the moving escalator.

Time to walk up the moving escalator = Length of the escalator / Relative speed between the person and the escalator when the escalator is moving.

Therefore, the time it would take for the person to walk up the moving escalator can be calculated by using the formula: Time = L / (L/60 - E).