Working with Multi-Part RatiosDate: 05/21/2007 at 20:38:06 From: Joshua Subject: Ratios with three parts I've been studying for the ACT test and can't seem to remember how to do ratios with three parts like 2:3:6. I fully understand normal ratios like 1:4. No need to cover the basics of ratios. In the three part ones I find it hard to understand how each of the numbers relates to the other two, though. Using my earlier example, how does the 2 relate to the 3 and 6? The 3 to the 2 and 6? If you could please give me a few examples of their uses along with explanations of the problems I would be much obliged! Respectfully, - Joshua Date: 05/29/2007 at 22:29:16 From: Doctor Peterson Subject: Re: ratios with three parts Hi, Joshua. The usual situation with this sort of ratio would involve dividing something (say, an inheritance) among three people in the ratio 2:3:6. Imagine taking the whole and dividing it up this way: +---+---+---+---+---+---+---+---+---+---+---+ | 2 | 3 | 6 | +---+---+---+---+---+---+---+---+---+---+---+ That is, person A gets 2 parts, B gets 3, and C gets 6 (all the parts being equal). How many parts are there in all? 2 + 3 + 6 = 11. What fraction of the whole does A get? He gets 2 of the 11 parts, or 2/11. What amount of a $99,000 inheritance does A get? 2/11 times 99,000 = $18,000. You can do the same thing with any number of parts, e.g. 1:2:5:3:6:7. Just add the parts to get the total number of parts, and use that as the denominator to find the fraction corresponding to each. If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/ Date: 05/31/2007 at 13:22:02 From: Joshua Subject: Thank you (Ratios with three parts) Dear Doctor Peterson, Thank you for your speedy reply to my ratio question! I understood your example and explanation without any trouble. Gratefully, - Joshua |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994- The Math Forum at NCTM. All rights reserved.
http://mathforum.org/dr.math/