The Solution.
Two angles that are supplementary sum up to 180 degrees, this means that:
[tex]\angle A+\angle B=180^o[/tex][tex]\begin{gathered} \text{Where }\angle A=x-16 \\ \angle B=3x+28 \end{gathered}[/tex][tex]\begin{gathered} x-16+3x+28=180 \\ \text{Collecting like terms, we get} \\ x+3x-16+28=180 \end{gathered}[/tex][tex]\begin{gathered} 4x+12=180 \\ 4x=180-12 \\ 4x=168 \\ \text{Dividing both sides by 4, we get} \\ x=\frac{168}{4}=42 \end{gathered}[/tex]To find angle A, we shall substitute 42 for x in the expression that defines angle A.
[tex]\begin{gathered} \angle A=x-16 \\ \angle A=42-16=26^o \end{gathered}[/tex]Therefore, the correct answer is 26 degrees.