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Help needed with a 7th grade math question! Oh my word, I hate math! Can somebody help with this problem solving question? Your cousin is 26 yrs older than your sister. The product of their ages is 560. How old is your sister? Now, I know the answer because I looked in the back of the book. I need to know, what strategy to use? I can post the answer if it helps. Can somebody explain it? Thank you! |
40 and 14 - process of elimination LOL edit: by the way i suck at math without a calculator and i could totally be wrong in thinking the product is the answer of two numbers being multiplied. |
OK. I am a Junior in high school with an A+ in Algebra II, and I can't figure this out!! I got a D in 7th grade Math (and 8th grade. and failed 9th grade math and had to go to summer school. finally turned it around last year! haha) My brain tells me that you should divide 560 by 26...and then you get approx. 21 and then 26 X 21 should be 560...but it's not. Let me get a calculator. OK!!!! 560/ 26 = 21.53846154. If you round that to 21.54, then you multiply it by 26, the answer is 560.04, which is rounded down to 560. so basically, 560/26 = 21.54 X 26 = approx. 560 So the sister is 21.54 years old. am I right!? haha |
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I do think that is what product means but.......??? Process of elimination? I am really, really dumb when it comes to this stuff. |
wuuuuuuut!? that makes no sense!! alright....hang on. I mean, yeah the 14 makes sense. but I can't think of a formula that would get you that answer, and usually stuff you learn in school doesn't depend on the process of elimination. OK! I see that my problem was that I did it as if the cousin was 26. when she is actually 26 years OLDER. OK ok ok. ETA: Process of elimination is when you keep putting numbers together until you get the right answer. |
process of elimination meaning trying things out until something works LOL 560 / 10 is 56 - 10 and 56 are not 26 numbers apart. so i tried 12. 560/12=46 nope 560/13=43 43-13=30 getting closer 560/14=40 40-14=26 let me break out a pen and some paper to see if i can come up with a logical answer to this |
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Your cousin is 26yrs older, so that means in math terms: 26+x Your sister is x You're solving for x (26+x)*x = 560 multiply x You get x^2 +26x = 560 Move the 560 x^2 + 26x -560 = 0 Factoring is fun! (x+40)(x-14) = 0 Now solve each individually, and only one will make sense. x+40=0 x=-40 WRONG! x-14=0 x=14 Yay! |
oh good Addielove already typed it out. that's what i did too after much thought on how to do that stuff again. LOL |
I got a headache. Too much math. |
LOL I love math. But I'm Asian, so I guess that's to be expected. :D I also play the piano ... :D |
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Show off :p No, just kidding!! Good for you for knowing that math problem. all through dinner I was trying to figure it out on a piece of paper hahaha. |
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I admit it took me a few minutes to remember what to do. It's been more than five years since I've been in a math class. *sigh* How time flies. |
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