Two parcel sizes

At a distribution centre, the number of express parcels is \(\frac{3}{7}\) of the number of standard parcels. A standard parcel has mass \(12\) kg and an express parcel has mass \(20\) kg. The total mass is \(2880\) kg. Let \(s\) be the number of standard parcels and \(e\) be the number of express parcels.

1. Using the ratio information, form an equation in \(s\) and \(e\).[1]
2. Using the total mass, form another equation in \(s\) and \(e\).[1]
3. Solve the equations obtained in (a) and (b) to find the number of parcels of each type.[3]
4. Hence, find the total number of parcels.[1]