Rates and FractionsDate: 1/23/96 at 21:4:46 From: Anonymous Subject: ratios Find out each rate as a fraction in simplest form. 1. 24 laps in 12 minutes 2. 180 miles with 15 gallons 3. $6 for 24 ounces 4. 25 heartbeats in 10 seconds solve these proportions 1. 9/4 = x/28 2. 5/x = 15/24 3. 3/20 = 6/x Date: 6/13/96 at 20:38:5 From: Doctor Lisa Subject: Re: ratios Hi! Let's first deal with the first 4 questions you have that involve reducing each rate to simplest form. First, rewrite the the words into a fraction. In number 1, this would be 24 laps/12 minutes. I would next see what number I can divide into both top and bottom of the fraction. In this case, you can divide 12 into both top and bottom. That would make the fraction 2 laps/1 minute. This should help you deal with the other 3 problems you listed. With the second set of questions, you will use the cross-products property of proportions. If you have a proportion that looks like a/b = c/d, then a*d = b*c. So in the first problem you gave, 9/4 = x/28, 9*28 = 4*x.9*28 = 252. So 252 = 4*x. To get x by itself you must divide both sides by 4. 252/4 = 63. So 63 = x. I hope this will help you answer the other 2 problems. -Doctor Lisa, The Math Forum |
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