Problem

The list of numbers shown below represents the masses, in kg, of nine items that are to be moved from one factory to another.

$180 \quad 300 \quad 250 \quad 410 \quad 240 \quad 120 \quad 230 \quad 310 \quad 190$

The items will all be moved, by van, at the same time.

Each van can carry at most 600 kg.

(a) Calculate a lower bound for the number of vans required.

(b) Use the first-fit bin-packing algorithm to allocate the items to vans.