8.1

Section 8.1 Direct Variation and Proportion

Example 1) If Y varies directly as X and Y=15, when X=24 find X when Y is 25

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Example 2) If P is directly proportional to R-2, and P=20 when R=6, find P when R=12

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Example 3) The electrical resistance is Ohms of a wire varies directly as its length if a wire 110cm long has a resistance of 7.5 Ohms what length will the wire have a resistance of 12 Ohms. (The answer should be 176cm, sorry for the inconvenience) media type="custom" key="8692894"

Section 8.1 Direct Variation and Proportion 1) If Y varies as X, and y=6 when X=15, find Y when x=25

2) If S is directly proportional to T, and S=40 when T=15, find T when S=64

3) If P is directly proportional to Q, and P=9 when Q=7.5, find Q when P=24

4) If S varies directly as R, and S=12 when R=2, find S when R=5

5) If W varies directly as 2X-1, and W=9 when X=2, find x when W=15

6) If the sales tax on a $60 purchase is $3.90, what would it be on a $280 purchase?

7) A real estate agent made a commission of $5400 on a house that sold at $120,000. At this rate, what commission will the agent make on a house that sells for $145,000?

8) The acceleration of an object varies directly as the force acting on it. If a force of 240 newtons causes and acceleration of 150 m/s^2, what force will cause an acceleration of 100 m/s^2?

9) A public-opinion poll found that of a sample of 450 voters, 252 favored a school bond measure. If 20,000 persons vote, about how many are likely to vote for the bond measure?

10)The stretch in a loaded spring varies directly as the load it supports. A load of 15kg stretches a certain spring 3.6 cm. What load would stretch the spring 6 cm?