Let, Matt's age be x years and Emily's age be y years.
Matt is 9 years older than twice Emily’s age .
It can be written as,
[tex]x=2y+9\ldots\ldots\ldots\ldots(1)[/tex]
And sum of their ages is 90
[tex]x+y=90\ldots\ldots\ldots\ldots\text{.}(2)[/tex]
Put the value of x from equation (1) in equation (2).
[tex]\begin{gathered} x+y=90 \\ (2y+9)+y=90 \\ 3y=81 \\ y=27 \end{gathered}[/tex]
Put the value of y in equation (1),
[tex]\begin{gathered} x=2y+9 \\ x=2(27)+9 \\ x=63 \end{gathered}[/tex]
Hence, the Matt's age is x= 63 years and Emily's age is y=27 years.
