10.(i)  A water tank has steps inside it. A monkey is sitting on the topmost step (i.e., the first step). The water level is at the ninth step.

 (i) He jumps 3 steps down and then jumps back 2 steps up. In how many jumps will he reach the water level?

Answers (1)
H Harsh Kankaria

Let the number of steps moved down be represented by positive integers and the number of steps moved up by negative integers.

Given,

Monkey is at the step = 1

Now,

The step after:

1st jump  = 1 + 3 = 4

2nd jump  = 4 + (-2) = 2

3rd jump  = 2 + 3 = 5

4th jump  = 5 + (-2) = 3

5th jump  = 3 + 3 = 6

6th jump = 6 + (-2) = 4

7th jump  = 4 + 3 = 7

8th jump  = 7 + (-2) = 5

9th jump  = 5 + 3 = 8

10th jump = 8 + (-2) = 6

11th jump = 6 + 3 = 9

Therefore, after 11 jumps, the monkey reaches the water level which is at the ninth step.

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