Water from rivers and streams is often unsafe to drink because of sediments and contaminants. One primitive way that water has been filtered in the past (and is still occasionally employed by avid campers and survivalists) is to use a charcoal filter, through which the water is allowed to trickle. Suppose three campers make three charcoal filters. The first two campers make their filters using water bottles, each of which can filter enough water for all three campers in 8 hours. The third filter is made from a two-liter soda bottle and can filter the same amount of water in 4 hours. How long will it take the three filters working together to filter enough water for all three campers?
A.
B. 1 hour
C.
D. 2 hours
Answer:D
Water from rivers and streams is often unsafe to drink because of sediments and contaminants. One primitive way that water has been filtered in the past (and is still occasionally employed by avid campers and survivalists) is to use a charcoal filter, through which the water is allowed to trickle. Suppose three campers make three charcoal filters. The first two campers make their filters using water bottles, each of which can filter enough water for all three campers in 8 hours. The third filter is made from a two-liter soda bottle and can filter the same amount of water in 4 hours. How long will it take the three filters working together to filter enough water for all three campers?
A. B. 1 hour C. D. 2 hours
Explanation: D