Question

if a certain number is added to the numerator and denominator of 9/13 the result is 9/11. find the number

Answer 1

We have the following:

When they tell us a certain number, we will assume a value x.

This number is added to the numerator and denominator of the fractional number 9/13 and gives us the result 9/11.

it is as follows

`(x+9)/(x+13)=(9)/(11)`

solving for x:

`\begin{gathered} (x+9)/(x+13)=(9)/(11) \\ 11\cdot(x+9)=9\cdot(x+13) \\ 11x+99=9x+117 \\ 11x-9x=117-99 \\ 2x=18 \\ x=(18)/(2)=9 \end{gathered}`

Therefore, the certain number is 9