What do you call a proportion when an increase in one quantity results in a decrease in another quantity or vice versa?

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It takes 4 men in 6 hours to repair a kitchen. How long will it take 8 men to do the job if they work at the same rate?

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If 3 boys can do their IPT in 12 days, how long will it take 6 boys to do the same task?

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4 people can paint a fence in 3 hours. How long will it take 6 people to paint it?

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20 workers can build a house in 30 days. Another house of the same design hired 10 more workers. How many days will it take them working at the same rate to build the similar house?

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35 workers can build a house in 16 days. How many days will it take 28 workers working at the same rate to build the same house?

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A farmer has enough feed to feed 300 hens for 20 days. If he buys 100 more hens, how long would the same amount feed the total hens?

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