Answer:
Step-by-step explanation:
This can be set up like an inequality. Â Chances are just as likely that you are in ratios and proportions, but since I'm not sure, I'm going with the easier way for this particular situation. Â The inequality, before reducing, is:
20 < 4x < 40,
which states that a 4 minute shower uses less than 40 gallons but greater than 20 gallons, where x is the number of gallons of water. Â Therefore,
5 < x < 10 results when you simplify. Â This puts things in terms of 1 minute now. Â This states that a 1 minute shower uses less than 10 gallons of water but more than 5 gallons. Â We got this by dividing everything by 4.
Now that things are in terms of a single minute, all you have to do is multiply the greatest number of gallons by 18 and the least number of gallons by 18 (and the x as well) to get the number of gallons used in an 18 minute shower as a range:
90 < 18x < 180
