Economies of scale occur when:
a. average fixed costs are falling.
b average fixed costs are constant.
c long-run average total costs rise as output increases.
d long-run average total costs fall as output increases.

d long-run average total costs fall as output increases.

Explanation:

Economies of scale are cost benefits enjoyed by companies when they increase production. Fixed costs are spread over the units produced. When there is a high level of production, the fixed costs are spread over a large number of goods, which reduces the cost element per unit.

Economies of scale also apply to variable costs. The expanded production increases efficiency in the production process. This reduces the average variable costs. Economies of scales can be both internal and external. When a company has economies of scale, its products tend to be more competitive in the market.

x=3

step-by-step explanation:

this is really simple i saw that there was only one term (5x) and thought if that was 15 what would i have to multiply everything else to get it there? well if 5x became 15 then x would have to be 3 so plug the 3 in the x for the other equations and you get 15 for the other ones. so there you go. : )

answer; coefficient of correlation;