Question $1$: A record distributor has warehouses in London, Bristol, and Leeds. It distributes

to shops in all those location as well as Glasgow. It currently has $40$ copies in the London

warehouse, $40$ in the Bristol warehouse and $50$ in the Leeds warehouse. It is expected to sell

$30$ copies in each shop location this month. The costs of shipping from each warehouse to

each location is below.

Determine how much demand can be met at minimum cost.