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Solve the following variation problems using the proper formula.
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1. |
In building a brick wall, the amount of time it takes to
complete the wall varies directly with the number of
bricks in the wall and varies inversely with the number
of bricklayers that are working together. A
wall containing 1200 bricks, using 3 bricklayers, takes
18 hours to build. How long would it take to build a
wall of 4500 bricks if 5 bricklayers worked on it?
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2. |
A video store rents DVDs, and the weekly total number
varies directly with the total inventory, and
varies inversely with the cost of each rental tape.
The store in Acme, NY, last week rented a total of 3000
DVDs when its inventory was 9600 and the cost per rental
was $2.40. If its inventory does not change, what
would be the effect on the weekly total number of
increasing the cost per rental to $3.00?
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3. |
A car's stopping distance varies
directly with the speed it travels, and
inversely with
the friction value of the road surface. If a car
takes 60 feet to stop at 32 mph, on a road whose
friction value is 4, what would be the stopping distance
of a car traveling at 60 mph on a road with a friction
value of 2?
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4. |
A ball is dropped from a window of a building. The
distance it falls varies directly with the square of the
time it falls. If a ball can fall 8 feet in 0.5
seconds, how far will it fall if it takes 2.5 seconds
for it to hit the ground? |
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5. |
In a power plant, the power produced
varies directly with the amount of water available, and
varies inversely with the temperature of the water.
The plant has a power rating of 100,000 when there is a
flow of 40,000 gallons of water per hour, and the
temperature of the water is 41º. Find the power
rating produced if the amount of water drops to 30,000 gallons
per hour, and the temperature rises to 60º.
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