1 Two new airconditioning units are charged for the first ti

1. Two new air-conditioning units are charged for the first time. To be fully charged, unit A needs 20 ounces of refrigerant. Unit B needs 15 ounces. Find the ratio and express as a fraction of the amount of refrigerant used in unit A to the amount used in unit B.

2. An installer compares the areas of a circular duct and a rectangular duct. The 6-inch by 5-inch rectangular duct has an area of 30 sq in. The 5 1/2-inch diameter circular duct has an area of about 24 sq in. What is the ratio of the area of the circular duct to the area of the rectangular duct?

3. If a compressor pulley has a 5 3/4-inch diameter and a motor pulley has a 2 3/4-inch diameter, what is the ratio of the revolutions per minute for the motor pulley to the revolutions per minute for the compressor pulley expressed as a fraction in lowest terms?

Solution

1)

ratio of the amount of refrigerant used in unit A to the amount used in unit B =20:15

ratio of the amount of refrigerant used in unit A to the amount used in unit B =5*4:5*3

ratio of the amount of refrigerant used in unit A to the amount used in unit B =4:3

amount of refrigerant used in unit A to the amount used in unit B =4_/3

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2)rectangular duct has an area of 30 sq in ,circular duct has an area of about 24 sq in

ratio of the area of the circular duct to the area of the rectangular duct =24:30

ratio of the area of the circular duct to the area of the rectangular duct =4*6:5*6

ratio of the area of the circular duct to the area of the rectangular duct =4:5

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3)

ratio of the revolutions per minute for the motor pulley to the revolutions per minute for the compressor pulley

= ratio of diameter of the compressor pulley to the diameter of the motor pulley

=5³/₄ : 2³/₄

=²³/₄ : ¹¹/₄

=23:11