IAL 2025 June D1 Q1

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.