You can buy 3 post cards for $5.40 , 6 post cards for $10.80 or 9 postcards for $16.20.what is the constant of proportionality for buying post cards?

Deshawn uses 3/4 of a box of rice to cook dinner the portion he uses weighs 12 ounces right and solve an equation to find the weight of the full box of rice

Acoffee shop orders at most $3,500 worth of coffee and tea. the shop needs to make a profit of at least $1,900 on the order. the possible combinations of coffee and tea for this order are given by this system of inequalities, where c = pounds of coffee and t = pounds of tea: 6c + 13t ≤ 3,500 3.50c + 4t ≥ 1,900 which graph's shaded region represents the possible combinations of coffee and tea for this order?

The domain of the following relation: r: {(3, 5), (8, 6), (2, 1), (8, 6)} is (1 point) no domain exists {1, 5, 6} {3, 8, 2, 8} {2, 3, 8}