Question

Benjamin is 20 inches long and weighs 8 lbs, how much does james weigh if he is 68 inches

Answer 1

27.2 lbs

Explanation:

For this we use proportions:

If this is a direct proportion, that means as Benjamin's height increases so does his weight. This can be expressed as a ratio:

Benjamin's length : Benjamin's weight

or

20 inches : 8 pounds

so,

68 inches : x

We use x to represent the missing weight. In order to find x, we express the two ratios as fractions:

`(20)/(68) = (8)/(x)`

Then we use cross multiplication and get our x:

`(68) * (8) = (20) * (x) \\ 544 = 20x \\ 20x = 544 \\ (20x)/(20) = (544)/(20) \\ x = 27.2`