Two 3D-printing materials

Flexible filament costs \(a\) cents per metre and rigid filament costs \(b\) cents per metre. An order of \(12\) m of flexible filament and \(18\) m of rigid filament costs \(\$8.70\). Another order of \(20\) m of flexible filament and \(10\) m of rigid filament costs \(\$9.50\).

1. Form two equations in \(a\) and \(b\) to represent the two orders.
2. Solve the equations obtained in (a) to find \(a\) and \(b\).
3. Hence, find the combined cost of \(5\) m of each material.