Need a solution to my question please.

For students of class 6-8 (age 12 to 14)
Raad Shahmat
Posts: 1
Joined: Thu Dec 14, 2017 9:04 pm

Need a solution to my question please.

Unread post by Raad Shahmat » Thu Dec 14, 2017 9:11 pm

You have 7 boxes in front of you and 140 kittens are sitting side-by-side inside the boxes, 20 in each box. You want to take some kittens as your pets. However the kittens are very cowardly. Each time you chose a kitten from a box, the kittens that are in that box to the left of it go to the box in the left, the kittens that are in that box to the right go to the box in the right. If they don’t find a box in that direction, they simply run away. After taking a few kittens, you see that all other kittens have run away. At least how many kittens have you taken?

User avatar
Tasnood
Posts: 46
Joined: Tue Jan 06, 2015 1:46 pm

Re: Need a solution to my question please.

Unread post by Tasnood » Tue Feb 13, 2018 10:34 pm

We need to take minimum amount of kittens.
Firstly, we will take the rightest kitten of the first box. So, the rest $7$ kittens, on the left, will simply run away.
In the $2^{nd}$ box, let the leftest kitten has been taken. So, $7$ kittens at right will go to the $3^{rd}$ box. In the $3^{rd}$ box, there will be $(6+7)=13$ kittens in total.
Next time, let the leftest has been taken from the $4^{th}$ box. So, in the $5^{th}$ box, there will be $(12+7)=19$ kittens in that box.
In this way, $6$ times we will take the leftest kitten and at last, all will simply run away.
So, we will take minimum $7$ kittens in total

Post Reply