Option C. $210
Let reservation charge be x [common for adult and child]
Reserved ticket for an child costs \$111 [ i.e. \$327 – $216 ]
Basic fare of Child, $\frac{\$216 - x}{2}$ = $111 – x [ costs half the regular fare for an adult ]
gives x = $6
therefore, Basic fare of Adult = Cost of reserved ticket – Reservation charge
= \$216 – $6 = $210