Chapter 7: Unit Conversions (Proportion method) If a student weighs 80 kg, how much does he weigh in...

Chapter 7: Unit Conversions (Proportion method)

If a student weighs 80 kg, howmuch does he weigh in pounds?

Step 1. Find a conversion factor that relates the units of interest to one another (page 34 table).

1 kg ≈ 2.205 pounds

Chapter 7: Unit Conversions


Step 2. Express the conversion factor as a ratio (fraction):

1 kg 2.205 pounds




Step 3. Express the problem as aratio with an unknown:

80 kg ?



Step 4. Set up a proportion equation such that the units in bothnumerators are the same and the units in both denominators are thesame:

80 kg ?


1 kg 2.205 pounds

=


Step 5. Solve for the unknown:

80 kg (2.205 pounds)


1 kg =?

= 176.4 pounds?


Step 6. Check that the answer makes sense


= 176.4 pounds?

Chapter 7: Unit Conversions (Unit canceling method)

Convert 2.80 kg to pounds.

Step 1. Write the problem as an equation.

2.8 kg = ? pounds



Step 2. Find a conversion factor such that the units cancel (page 34).

1 lb 0.454 kg




Step 3. Place the conversion factor into the equation.

2.80 kg X = ?


1 lb 0.454 kg


Step 4. Solve the equation; multiply 2.80 kg by the conversion factor:


2.80 kg X ≈ 6.17 lb 1 lb 0.454 kg

Chapter 7: Word Problems Requiring Multiple Steps

Transgenic sheep can secrete a human protein,AAT, into their milk. AAT is valuable in the treatment of emphysema. The concentration of AAT in the milk is 15 g/L. A sheep can produce 400 liters of milk each year. AAT isworth $110/gram. What is the value of a year’sproduction of AAT from such transgenic sheep?

= $?/year400 L year

15 g L

X$110gram

X

= $660,000/year

Chapter 7: Unit Conversions (Proportion method) If a student weighs 80 kg, how much does he weigh in...

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