If the system of linear equations: \( x + y + z = 6 \), \( x + 2y + 5z = 10 \), \( 2x + 3y + \lambda z = \mu \) has infinitely many solutions, then the value of \( \lambda + \mu \) equals:
\( 12 \)
\( 16 \)
\( 22 \)
\( 28 \)