Mr. and Mrs. Ahuja weigh $x$ kg and $y$ kg respectively. They both take a dieting course at the end of which Mr. Ahuja loses $5$ kg and weighs as much as the wife weighed before the course. Mrs. Ahuja loses $4$ kg and weighs $7$/$8$th of what her husband weighed before the course. From two equations in $x$ and $y$ and hence find their present weights.
I tried the following,
Mr. Ahuja's weight before the course$=$$x$ kg
Mrs. Ahuja's weight before the course$=$$y$ kg
After dieting course
Mr. Ahuja's weight: $E_1 =>x-5=y$
Mrs. Ahuja's weight: $E_2 =>y-4=\frac78 x$
Solving for $x$, I am getting $-27$ which is not possible.
Where did I go wrong?