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The sum of the numerator and denominator of a certain fraction is 10. If 1 is subtractedboth the numerator and denominator, the fraction is decreased by 2/21 .Find the fraction. |
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Answer» suppose initial fraction is x/(10-x) now new fraction (x-1)/(9-x) so (x-1)/(9-x)=x/(10-x) -2/21 (10x-x*x-10+x-9x+x*x)/(9-x)(10-x)=-2/21 21(2x-10)=-2(x*x-19x+90) 42x-210=-2x*x+38x-180 2x*x+4x-30=0 x*x+2x-15=0 (x+5)(x-3)=0 so x=-5 or x=3 so fraction is either -5/15=-1/3 or 3/7 |
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