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) 0.5 HOUR
B)1 HOUR
C)1.5 HOURS
D)2 HOURS
@ManalFayed see halcyonheather’s posts in this thread, which is fairly recent and includes very similar problems:
The same method can be used on this question.
thank you