A student plans to study Mathematics for $x$ hours and Physics for $y$ hours a day, and has at most 10 hours. Which constraint describes this?

Explanation

1. 01

   Write each resource as (amount used per unit) × (number of units), added over the products.

2. 02

   'At most' or 'available' gives ≤, 'at least' or 'must give' gives ≥; a profit is maximised and a cost minimised.