"A number is 11 more than another number" can be expressed as
[tex]x=y+11[/tex]"Twice the sum of the two numbers is 42" can be expressed as
[tex]2(x+y)=42[/tex]So, these two equations for a system. Let's combine them to find y in the first place
[tex]\begin{gathered} 2(x+y)=42 \\ 2(y+11+y)=42 \\ 2(2y+11)=42 \\ 2y+11=\frac{42}{2} \\ 2y+11=21 \\ 2y=21-11 \\ 2y=10 \\ y=\frac{10}{2} \\ y=5 \end{gathered}[/tex]Then, we find x
[tex]x=y+11=5+11=16[/tex]