Question

Barb is making a bead necklace. She strings 1 white bead, 3 blue bead, then 1 white bead, and so on. Write the numbers for the the eight beads that are white. What is the rule for the pattern?

Answer 1

1,5,9,13,17,21,25,29

Explanation:

From the information given.

Let represent the number of white beads with x and the number of blue beads with y. So, the beads can be illustrated as:

bead color

1 x

2 y

3 y

4 y

5 x

6 y

7 y

8 y

Suppose n denotes the no. of beads that are white.

Then the subsequent no is ( n + 4).

Since the first number n = 1

Then the subsequent numbers will follow the pattern of adding 4 to the number.

i.e.

n = 1 + 4 = 5

n = 5 + 4 = 9

n = 9 + 4 = 13

n = 13 + 4 =1 7

n = 17 + 4 = 21

n = 21 + 4 = 25

n = 25 + 4 = 29

Thus, the number for the first eight beads that are white are:

1,5,9,13,17,21,25,29

The pattern shows odd numbers only.