Question

A monkey jumps 3 steps up and 1 step back on a staircase. How many jumps will he have to make to reach
the bananas kept on the 13' stair?​

Answer 1

So, it will take 16 jumps. But that is not true as at the 11th jump he descends 3 steps and reaches the 8th step and so it will not go back 2 steps

Answer 2

Monkey Jumps 3 steps down and 2 steps up so, in total he jumped 1 step down.

Therefore , In every single jump the monkey reaches 2 steps up.

In 1st jump , the monkey reaches = ( 3-1) = 2 steps up

After 1st jump, he has to jump for ( 13 -2) = 11 steps more

In 2nd jump, the monkey reaches = ( 3-1) = 2 steps

After 2nd jump,the monkey has to jump for ( 11-2) = 9 steps

In 3rd jump the monkey covers = ( 3-1 ) = 2steps more

After 3rd jump,the monkey has to jump for ( 9 -2) = 7

In 4 th jump the monkey will cover = ( 3-1) = 2 steps more.

After 4th jump the monkey has to jump for ( 7-2) = 5 stairs

In 5 th jump the monkey will cover ( 3-1) = 2 steps more

After 5th jump the monkey has to jump for ( 5-2) = 3 steps more

In 6th jump the monkey covers ( 3-1)= 2 steps.

After 6th jump the monkey has to jump for ( 3-2) = 1 steps

Here 1 step will be remain to reach up to the bananas.

Hence the monkey has to jump 6 jumps and in 7th jump attempts, the monkey will reach to the bananas kept on 13 stairs.

Ans :-  The monkey has to jump 6 jumps and in 7th jump attempts, the monkey will reach to the bananas kept on 13 stairs.

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