In a street the average age of 15 boys is 19 years . If the age of one more boys is included , the average decreased by $\large\frac{1}{2}$ What is the age of the new boy ?

Question

$\begin{array}{1 1} 5 \;years \\ 11 \; years \\ 19\;years \\ 14 \;years \end{array} $