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## Ratio, Rate, and Proportion

If it takes 5 identical firetrucks 5 minutes to pump 5 kiloliters of water onto a fire, how long will it take 8 firetrucks pump 8 kiloliters? Hint: the answer isn't 8 minutes.

# Inverse Variation

The value of $$y$$ varies inversely with $$x.$$ If $$y=6$$ when $$\displaystyle x=\frac{8}{3},$$ what is the value of $$y$$ when $$x=5 ?$$

Suppose there is a water faucet that can fill a $$575$$-liter-tank in $$100$$ minutes. How many faucets do we need to fill this tank in $$4$$ minutes?

A cruise ship rents for $$\800$$ a day. If $$8$$ people go on a trip by this ship, what is the cost per capita?

Calvin is planning to visit his hometown during Thanksgiving Holidays. It will take $$9$$ hours if he drives at $$85 \text{ km/h}.$$ How long will it take if he drives at $$102 \text{ km/h} ?$$

If $$z$$ varies directly as $$x$$ and inversely as $$y,$$ how many times larger does $$z$$ get if $$x$$ is increased by $$2$$ times and $$y$$ is decreased by $$7$$ times?

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