Page 428 - Basic College Mathematics with Early Integers

S E C T I O N 5.5 I WEIGHT AND MASS: U.S. AND METRIC SYSTEMS OF MEASUREMENT 405

Example 8 Convert 2.35 cg to grams. PRACTICE 8
Convert 56.2 cg to grams.
Solution: We list the units of mass in a chart and move from centigrams to grams.
kg hg dag g dg cg mg

2 units to the left

02.35 cg=0.0235 g
2 places to the left
Work Practice 8

Objective Performing Operations on Metric System
Units of Mass

Arithmetic operations can be performed with metric units of mass just as we per-
formed operations with metric units of length.We convert each number to the same
unit of mass and add, subtract, multiply, or divide as with decimals.

Example 9 Subtract 5.4 dg from 1.6 g. PRACTICE 9
Subtract 3.1 dg from 2.5 g.
Solution: We convert both numbers to decigrams or to grams before subtracting.

5.4 dg=0.54 g or 1.6 g =16 dg

1.60 g 16.0 dg
– 0.54 g – 5.4 dg
1.06 g 10.6 dg
The difference is 1.06 g or 10.6 dg.

Work Practice 9

Example 10 Calculating Allowable Weight in an Elevator PRACTICE 10
Twenty-four bags of cement
An elevator has a weight limit of 1400 kg. A sign posted in the elevator indicates weigh a total of 550 kg. Find the
that the maximum capacity of the elevator is 17 persons. What is the average average weight of 1 bag,
allowable weight for each passenger, rounded to the nearest kilogram? rounded to the nearest
kilogram.
Solution: To solve, notice that the total weight of 1400 kilograms 17 average
weight.
82.3 kg L 82 kg
17 1400.0 kg
-136
40
-34
60
-51
9
Each passenger can weigh an average of 82 kg. (Recall that a kilogram is slightly
over 2 pounds, so 82 kilograms is over 164 pounds.) Answers
8. 0.562 g 9. 2.19 g or 21.9 dg
Work Practice 10 10. 23 kg