Nik's age: x
Here is a system of equations that we can set up based on the information...
x+3y=54
2y+4x=80
Rearrange these...
x+3y=54
4x+2y=80
x+3y=54 solve an equation for y
4x+2y=80
2y=80-4x
y=40-2x
Plug in 40-2x for y in the other equation...
x+3(40-2x)=54
x+120-2x=54
-x+120=54
-x=-66
x=66
Nik is 66 years old.
Hope this helps! Best wishes:)
