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10. If 50% of (x- y) = 40% of (x + y), then what percent of x is y?(a) 10(1/9)% (b) 11(1/9)% (c) 13(1/9)% (d) 21(1/9)% |
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Answer» Answer: Option (b) Step-by-step explanation: Given:-50% of (x- y) = 40% of (x + y) To find:-If 50% of (x- y) = 40% of (x + y), then what percent of x is y? Solution:-Given that 50% of (x- y) = 40% of (x + y) =>50% × (x- y) = 40% ×(x + y) =>(50/100)× (x- y) = (40/100)× (x + y) = (1/2)×(x- y) = (2/5)× (x + y) =>(x -y)/2 = 2(x + y)/5 =>(x-y)/2 = (2x+2y)/5 On applying cross MULTIPLICATION then =>5(x-y) = 2(2x+2y) =>5x -4x = 4y +5y =>x = 9y -----(1) Let A% of x = y =>A% ×x = y =>(A/100)× x = y =>A×9y/100 = y =>A9y/100 = y On cancelling y both sides =>9A /100 = 1 =>9A = 1×100 =>9A = 100 =>A = 100/9% =>A = 11 1/9 % Answer:-The required percentage for the given problem is 11 1/9 % |
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