if one is added to both the numerator and denominator of a given fraction it becomes 4 by 5 if however 5 is subtracted from both the numerator and denominator fraction becomes 1 by 2 find the fraction
Answers
let the fraction be x/y
(x+1)/(y+1)=4/5
=> 5x-4y+1=0
(x-5)/(y-5)=1/2
=> 2x-y-5=0
by solving these eqns...
x=7
y=9
x/y=7/9
SOLUTION :
Let the numerator be x and denominator be y
Fraction = numerator/denominator
Fraction = x/y
A.T.Q
1st case :
x +1 / y +1 = 4/5
5(x +1) = 4(y +1)
5x + 5 = 4y + 4
5x - 4y = 4 -5
5x - 4y = -1.............(1)
2nd case :
x - 5 / y - 5 = 1/2
2 (x - 5 ) = 1 (y - 5)
2x - 10 = y - 5
2x - y = - 5 +10
2x - y = 5…………(2)
Multiply eq 2 by 4
8x - 4y = 20………..(3)
On Subtracting eq 1 from eq 3
8x - 4y = 20
5x - 4y = -1
(-) (+) (+)
------------------
3x = 21
x = 21/3
x = 7
Put this value of x in eq 1
5x - 4y = -1
5(7) - 4y = -1
35 - 4y = -1
35 +1 = 4y
36 = 4y
y = 36/4
y = 9
Fraction = x/y = 7/9
Fraction = 7/9
Hence, the fraction is 7/9
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