Question

The denominator of a rational number is twice sits numerator.if the numerator is decreased by 3and the denominator by 7,the number obtained is 2/5.find the rational. Number

Answer 1

numerator is x
denominator is 2x
numerator decreased by 3 is x-3
denominator decreased by 7 is 2x-7
x-3/2x-7=2/5
cross multiple
5(x-3)=2(2x-7)
5x-15=4x-14
5x-4x=15-14
x=1
therefore numerator is x=1
denominator is 2x=2*1=2