Basic Mathematics for College Students

Chapter 5 Summary and Review 487

A list of unit conversion factors for units of
time is given on page 450.

Convert 240 minutes to hours.

To convert from minutes to hours, we select a unit conversion factor

that introduces the units of hours and eliminates the units of minutes.

Since there is 1 hour for every 60 minutes, we will use:

To perform the conversion, we multiply.

Write 240 min as a fraction. Then

multiply by a form of 1:.

Multiply the fractions.

Do the division.

Thus, 240 minutes is equal to 4 hours.

 4 hr



240

60

hr

Remove the common units of minutes

from the numerator and denominator.

The units of hours remain.



240 min

1



1 hr

60 min

1 hr

60 min^

240 min

240 min

1



1 hr

60 min

This is the unit we want to introduce.

 This is the unit we want to eliminate (the original unit).

1 hr 

60 min

47. a. Refer to the ruler below. Each inch is divided
    into how many equal parts?
    b. Determine which measurements the arrows
    point to on the ruler.


48. Use a ruler to measure the length of the computer
    mouse.


49. Write two unit conversion factors using the fact that
    1 mile 5,280 ft.


50. Consider the work shown below.

a. What units can be removed?

b. What units remain?

100 min

1



60 sec

1 min



1 2 3

Inches

Perform each conversion.

51. 5 yards to feet


52. 6 yards to inches


53. 66 inches to feet


54. 9,240 feet to miles


55. feet to inches


56. 1 mile to yards


57. 32 ounces to pounds


58. 17.2 pounds to ounces


59. 3 tons to ounces


60. 4,500 pounds to tons


61. 5 pints to fluid ounces


62. 8 cups to gallons


63. 17 quarts to cups


64. 176 fluid ounces to quarts


65. 5 gallons to pints


66. 3.5 gallons to cups


67. 20 minutes to seconds


68. 900 seconds to minutes


69. 200 hours to days


70. 6 hours to minutes


71. 4.5 days to hours


72. 1 day to seconds

(^4 12)
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