Question

A jug holds 5 gallons of water. If a glass holds 4 ounces of water. How many glasses cam be drawn from the water jug?

Answer 1

160 glasses of water

Answer 2

Conversion Factors.

1 cup = 8 fluid ounces.

4 cups = 1 quart

4 quarts = 1 gallon

Solution

Use a method call unit fractions. It is simple to use. All you do is arrange the fraction so that 1 part of the unit fraction on the right cancels with 1 part of the fraction on its left. Then divide the numerator by the denominator when each has been multiplied. All this will become clearer if you follow the example below.

`\text{5 gallons} * (4 quarts)/(1 gal)*(4 cups)/(1 quart)*(8 oz)/(1 cup)*(1 glass)/(4oz)`

numerator: 5 * 4 * 4 * 8 * 1 = 640

denominator: 1 * 1 * 1 * 1 * 4 = 4

Answer: numerator/ denominator = 640/4 = 160 glasses / 5 gallons.