Lesson 19 Section 2 ## INVERSE PROPORTIONALITY |
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This means that if one of the quantities Example 1. Let us suppose that the Specifically: If 6 workers can do a job in 4 days, then how long will it take 12 workers?
Example 2. The speed that a car can achieve in 10 seconds is inversely proportional to its weight. (That is, the more the car weighs, the slower it will be going.) After 10 seconds, a car that weighs 2400 pounds can achieve a speed of 44 miles per hour. If the car weighed 1600 pounds, how fast would it be going?
1600 is to 2400 as 16 is to 24 as 2 is to 3. (After ignoring the 0's, we see that both 16 and 24 have a common divisor 8. Lesson 16, Question 7.) Now, the inverse ratio of 2 to 3 is the ratio 3 to 2. And since 3 = 3 is one and a half times 2. The speed therefore will be one and a half times 44: 44 + 22 = 66 miles per hour. When quantities are inversely proportional, we say that one of them varies inversely as the other. Thus the speed that a car can achieve in a given time varies inversely as its weight.
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