mama25angels Posted May 21, 2012 Share Posted May 21, 2012 Here are the two problems: Two years ago, Rick's age was 1 year less than twice Chris's age. Four years from now, Rick will be 8 years more than half Chris's age. How old are they now? Five years ago, Amos was one-fifth as old as his father. Five years from now, he will be three-sevenths as old as his father. Find their present ages. Thanks! Quote Link to comment Share on other sites More sharing options...
Snickerdoodle Posted May 21, 2012 Share Posted May 21, 2012 Chris 6 and Rick 9 (??) Quote Link to comment Share on other sites More sharing options...
nmoira Posted May 21, 2012 Share Posted May 21, 2012 Here are the two problems: Two years ago, Rick's age was 1 year less than twice Chris's age. Four years from now, Rick will be 8 years more than half Chris's age. How old are they now? Let x be Chris' age now. (You could choose Rick.) Two years ago: Chris = x-2 Rick = 2(x-2) - 1 Four years from now: Chris = x + 4 Rick = (x + 4)/2 + 8 Now we have to set up an equation. Rick's age two years ago plus 6 will be his age four years from now. There are other options, but all will give the same answer. 2(x-2) - 1 + 6 = (x+ 4)/2 + 8 2(2x - 4 - 1 + 6) = x + 4 + (8 * 2) 4x + 2 = x + 20 3x = 18 x = 6 Chris is six, Rick is nine (I figured out his age two years and added two). Quote Link to comment Share on other sites More sharing options...
Snickerdoodle Posted May 21, 2012 Share Posted May 21, 2012 See, I'm lazy. I just made a little guess and check table. My guess for the next one is 10yo and 30 yo. But I need to run out the door right now. Quote Link to comment Share on other sites More sharing options...
nmoira Posted May 21, 2012 Share Posted May 21, 2012 Five years ago, Amos was one-fifth as old as his father. Five years from now, he will be three-sevenths as old as his father. Find their present ages. Let x be Dad's age now. Five years ago: Dad: x - 5 Amos = (x - 5)/5 Five years from now: Dad = x + 5 Amos = 3(x + 5)/7 Setting up the equation. Amos's age five years ago plus 10 will be his age five years from now. (x-5)/5 + 10 = 3(x + 5)/7 7(x-5) + 350 = 15(x + 5) 7x - 35 + 350 = 15x + 75 8x = 240 x = 30 Dad is 30, Amos is 10. Quote Link to comment Share on other sites More sharing options...
nmoira Posted May 21, 2012 Share Posted May 21, 2012 See, I'm lazy. I just made a little guess and check table. My guess for the next one is 10yo and 30 yo. But I need to run out the door right now. :tongue_smilie: Quote Link to comment Share on other sites More sharing options...
mama25angels Posted May 21, 2012 Author Share Posted May 21, 2012 Let x be Dad's age now. Five years ago: Dad: x - 5 Amos = (x - 5)/5 Five years from now: Dad = x + 5 Amos = 3(x + 5)/7 Setting up the equation. Amos's age five years ago plus 10 will be his age five years from now. (x-5)/5 + 10 = 3(x + 5)/7 7(x-5) + 350 = 15(x + 5) 7x - 35 + 350 = 15x + 75 8x = 240 x = 30 Dad is 30, Amos is 10. Thank you!!! Quote Link to comment Share on other sites More sharing options...
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