Ans: A
The required number
The required number
$\begin{array}{cl}
= & C^{14}_3 + C^{15}_3 \\
= & 819
\end{array}$
Resources for HKDSE Mathematics
Resources for HKDSE Mathematics
$\begin{array}{cl}
= & C^{14}_3 + C^{15}_3 \\
= & 819
\end{array}$
