Question

A ladder has 10 steps.A labourer has to carry some weight to the top. He climbs the ladder 2 steps up in one second and 1 step down in the next second by dancing on a famous tune. In how many seconds he would reach the top.

Answer 1

labour goes in 1 sec = 2 steps
then,
he get down in next 2 sec = 1 step .
so, finally he goes up in 1 step in = 3sec .
hence , he goes 10 steps in =
3×10 = 30 sec .

Answer 2

Concept Introduction:

A laborer's net movement is one step in two seconds. But once he gets on top we have to calculate that time.

Given: A ladder has $10$ steps. A laborer has to carry some weight to the top. He climbs the ladder $2$ steps up in one second and $1$ step down in the next second by dancing on a famous tune.

To Find:

We have to find the value of, time taken by the labor to reach the top of the ladder.

Solution:

According to the problem,

In $2sec$ net movement of labor is $1$ step. Till $8$th step time taken is $8*2=16sec$ then after reaching $8$th step he moves $2$ steps up to reach $10$th step in $1$ sec hence total time taken to reach $10$th step is $= 16+1=17sec$.

Final Answer:

The value of time taken by the labor to reach $10$th step is $17sec$.

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