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the numerator of a fraction is one less than its denominator if 3 is added to each of the numerator and denominator the fraction is increased by 3 by 8 find the fraction |
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Answer» ong>Answer: 3/4 Step-by-step explanation: Let the denominator be x. A.T.Q., the NUMERATOR will be (x - 1). Original fraction = {\SF{{\dfrac{x - 1}{x}}}} x x−1
Now, as given in the question, 3 is added to both numerator and denominator. So, Numerator = x - 1 + 3 = x + 2 Denominator = x + 3 A.T.Q. {\sf{{\dfrac{x + 2}{x + 3}} = {\dfrac{x - 1}{x}} + {\dfrac{3}{28}} }} x+3 x+2
= x x−1
+ 28 3
On further solving, we get \Rightarrow{\sf{ {\dfrac{x + 2}{x + 3}} = {\dfrac{28(x - 1) + 3(x)}{(28)(x)}} }}⇒ x+3 x+2
= (28)(x) 28(x−1)+3(x)
\Rightarrow{\sf{ {\dfrac{x + 2}{x + 3}} = {\dfrac{28x - 28 + 3x}{28x}} }}⇒ x+3 x+2
= 28x 28x−28+3x
\Rightarrow{\sf{ {\dfrac{x + 2}{x + 3}} = {\dfrac{31x - 28}{28x}} }}⇒ x+3 x+2
= 28x 31x−28
Cross - multiplication. \Rightarrow⇒ 28x(x + 2) = (x + 3)(31x - 28) \Rightarrow⇒ 28x(x + 2) = x(31x - 28) + 3(31x - 28) \Rightarrow⇒ 28x² + 56x = 31x² - 28x + 93X - 84 \Rightarrow⇒ 28x² + 56x = 31x² + 65x - 84 Transposing the terms. \Rightarrow⇒ 28x² - 31x² = 65x - 56x - 84 \Rightarrow⇒ - 3x² = 9x - 84 \Rightarrow⇒ 3x² + 9x - 84 = 0 \Rightarrow⇒ 3(x² + 3x - 28) = 0 \Rightarrow⇒ x² + 3x - 28 = 0 Using Middle Term Factorisation, we get \Rightarrow⇒ x² - 4X + 7x - 28 = 0 \Rightarrow⇒ x(x - 4) + 7(x - 4) = 0 \Rightarrow⇒ (x + 7)(x - 4) = 0 Using zero product rule, we get \Rightarrow⇒ x + 7 = 0 and x - 4 = 0 \Rightarrow⇒ x = - 7 and x = 4 Here, x is a natural number, where x > 0. Hence, x = 4 The required fraction is : \Rightarrow{\sf{ {\dfrac{x - 1}{x}} }}⇒ x x−1
\Rightarrow{\sf{ {\dfrac{4 - 1}{4}} }}⇒ 4 4−1
\Rightarrow{\boxed{\sf{\red{ {\dfrac{3}{4}} }}}}⇒ 4 3
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