Consider steps moved down being represented by positive integers and then, steps moved up are represented by negative integers.
(1 mark)
Initially monkey is sitting on the top most step i.e., first step
In 1st jump monkey will be at step = 1 + 3 = 4th step
In 2nd jump monkey will be at step = 4 + (-2) = 4 – 2 = 2nd step
In 3rd jump monkey will be at step = 2 + 3 = 5th step
In 4th jump monkey will be at step = 5 + (-2) = 5 – 2 = 3rd step
In 5th jump monkey will be at step = 3 + 3 = 6th step
In 6th jump monkey will be at step = 6 + (-2) = 6 – 2 = 4th step
In 7th jump monkey will be at step = 4 + 3 = 7th step
In 8th jump monkey will be at step = 7 + (-2) = 7 – 2 = 5th step
In 9th jump monkey will be at step = 5 + 3 = 8th step
In 10th jump monkey will be at step = 8 + (-2) = 8 – 2 = 6th step
In 11th jump monkey will be at step = 6 + 3 = 9th step
(2 marks)
∴Monkey took 11 jumps to reach the water level at the 9th step
(1 mark)