Mrs Brown gets her class of 21 children to stand in a circle. She chooses the child in the first position to give one of 21 Valentine's cards anti-clockwise to the person next to their neighbour. The children keep passing the cards in this pattern until they all have one. The child at which position is last to receive a card?

The child who receive cards are: 21, 20,19, ... 1

the last who receive the card is number 1

Solution:

As per the problem we have

Mrs Brown gets her class of 21 children to stand in a circle. She chooses the child in the first position to give one of 21 Valentine’s cards anti-clockwise to the person next to their neighbor.

The children keep passing the cards in this pattern until they all have one.

It mean when the first child passes the card to second child then second child will have 20 cards.

when it will go from second child to 3rd child then third child will have 19 cards.

...

...

when it will go from 20th child to last child then the last child will have only one card in hand.

It mean the card can be distributed to a total of 21 student.

The student at 2nd position will be the last one to receive the card.