Final Exam Final Review

y varies inversely as x such that when x=12, y=9. Find y when x=27.

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• 9

• 18

Why can zero never be in the domain of an inverse variation?

• Division by zero is undefined.

• The graph of an inverse variation function will never go through the point​ (0,0).

• The graph of an inverse variation function will always be positive.

• Division by zero is always 0.

The amount of time it takes mail carriers to deliver the mail in one town is inversely proportional to the number of mail carriers delivering the mail.  With 10 mail carriers, it takes 6 hours to deliver the town’s mail. What is the number of hours it would take 6 mail carriers to deliver the town’s mail?

• 3

• 2

• 10

• 8

The time t required to drive a certain distance varies inversely with the speed r. If it takes 2 hours to drive the distance at 30 miles per hour, how long will it take to drive the same distance at 50 miles per hour?

• 1.2 hours

• 60 hours

• 750 hours

• about 3.33 hours

y varies inversely with x. If y = 40 when x = 16, find x when y = -5.

• -64

• -128

• -256

• -512

The current I in an electrical conductor varies inversely as the resistance R of the conductor. The current is 1/6  ampere when the resistance is 54432 ohms. What is the current when the resistance is 74088 ohms?

• 6/49 ​ amps

• 326,692 amps

• 9072 amps

• 49/6 amps

The number of hours to paint a house varies inversely with the number of painters working. A 2400-square foot house can be painted in 27 hours by 6 painters. How many painters would need to work in order to paint the house in 18 hours?

• 9 painters

• 8 painters

• 10 painters

• 11 painters

The time that a group of carpenters takes to build a deck is inversely proportional to the number of carpenters. If 3 carpenters can build a deck in 36 working hours, how many carpenters are needed to build a deck in 27 working hours?

• 2

• 3

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