x= # tickets Tom sold
3x+16= # tickets Steve sold
Add the amounts Tom and Steve sold and that will equal 104 total tickets sold.
x+(3x+16)=104
4x+16=104
Subtract both sides by 16
4x=88
Divide both sides by 4
x=22 # tickets Tom sold
Substitute the x=22 answer to find Steve's tickets sold
3x+16= 3(22)+16= 82 # tickets Steve sold
Hope this helps! :)