Operational Research

Can someone help me with this question please ?

A week before the skiing season, a trade fair is organised where skiers can buy or exchange their skiing equipment. A local retailer has decided to sell winter gloves at the trade fair. The retailer can buy gloves for a reasonable price of £10 per pair and sell them for £14 per pair. The retailer can sell all the unsold gloves later on for £7 per pair; however, there will be an additional associated inventory holding cost of £1 per unsold pair of gloves.
As there is no statistical data, the retailer estimates that they can sell any number between 100 and 120 pair of gloves, inclusive, with equal probabilities.

How many pairs of gloves should the retailer order to maximise they profit