The length of a paper clip chain is directly proportional to the number of paper clips. If a chain with 72 paper clips has a length of 108 inches, how long is a chain with 16 paper clips?

Directly proportional numbers are numbers that increases or decreases in the same ratio. To solve:

1) State the problem in ratios -

Let n be the missing length.

72/108 = 16/n

2) Cross multiply

72*n = 108*16

72n = 1728

3) To get n, divide both sides of the equation by 72

72n/72 = 1728/72

n = 24

Therefore, the chain with 16 paper clips is 24inches

To check, substitute the values -

72/108=16/n

72*n = 108*16

72*24 = 1728

1728 = 1728