A water tank has steps inside it. A monkey is sitting on the top most step. (ie, the first step) The water level is at the ninth step.
(a) He jumps $3$ steps down and then jumps back $2$ step up. In how many jumps will he reach the water level?
(b) After drinking water, he wants to go back. For this, he jumps $4$ steps up and then jumps back $2$ steps down in every move. In how many jumps will he reach back the top step?

$(a)$ Monkey Jumps $3$ steps down and $2$ steps up so, in total he jumped $1$ step down.Therefore , Now he is at $second$ step and water level is at the $ninth$ step.
Now, he will reach water level in $9-2=7$ jumps.

$(b)$ He jumps 4 steps up and 2 steps down ,so totally he climbs 2 steps up in 6 Jumps,Similarly we can divide 9 steps as follows
$\Rightarrow 9=2+2+2+3$
After reaching the third Step, As he jumps up $3$ more Steps He will reach the top step and till then there will be no more steps to climb.(Means after $3$ more Jumps he will reach the top step)

Now, the number of jumps he made to reach the top $=2\times 6+2\times 6+2\times 6+3=12+12+12+3=39$