Grades 5-6 Video Solutions 2023-2023_1-2

Video Transcription

Question 17. Goran has four blocks stacked as shown. In a single move, he can take some or all of the blocks from the top of the stack and place them upside down as shown. He wants  the blocks to be stacked in this order. What is the smallest number of moves he needs to make to get from this starting position to the correct order?  Let's start off by drawing our stack, like so. Next, to make the most efficient move possible, we will flip the top two blocks so that the three bottom blocks are in the  right order. Now we just need to get the top block to the bottom. To do this, we will flip like so, and then flip one more time, so the smallest number of moves needed to be made  will be B, three.

Video Summary

Goran needs to rearrange four blocks using the fewest moves, by flipping some or all from the top of a stack. Initially, he flips the top two blocks to correctly order the bottom three. Then, he flips all the blocks to move the top block to the bottom. Finally, he flips once more to achieve the correct order. The smallest number of moves required is three.