Problem number 17. The beads on a string alternate between black and white. Each block hides five beads. In total, how many white beads are hidden? To solve this problem, we need to figure out the beads that are hiding behind each block. For example, the bead before the first block is black, which means that since the beads are alternating, the first block should start with a white bead and then alternate for five colors. For example, it should look like this. It looks like five colors alternating, white, black, white, black, white, and we know it should start with white because the previous bead before the block is black. Similarly, we can do the same for the second block. The bead before the second block is black, so we know that this block should also start with a white bead, and indeed, if we look at this, we'll see that the pattern should be white, black, white, black, white, just like the first block. These two blocks have the same pattern of beads behind them. If we want to count the total number of white beads, we'll notice that there are three in the first one and three in the second one, and three plus three is six. This means that the total number of white beads hidden behind the two blocks is B, six.

alternating beads

white beads

hidden beads

pattern blocks

bead count