3 + y/4. If y=16, you just replace y by its value, and calculate the equation following the order of operations: Parenthesis, Multiplication and division, addition and subtraction.
3+y/4 = 3+16/4
You first calculate the division: 16/4 = 4
So 3 + 16/4 = 3+4
Then you just add both numbers and you get your result:
3+4 = 7.
So when y = 16, the value of 3+y/4 is 7.
Hope this Helps! :)