7
algebra

An electric vehicle charging station costs $0.35 per kWh. If a driver has $28 to spend, which inequality represents the maximum kilowatt-hours kk they can charge?

A

0.35k≤280.35k \leq 28

B

0.35k≥280.35k \geq 28

C

28k≤0.3528k \leq 0.35

D

k+0.35≤28k + 0.35 \leq 28

Correct Answer: A

Choice A is the correct answer. Per-unit pricing with a budget creates a maximum constraint.

  1. Cost structure: $0.35 per kWh means cost = 0.35k0.35k
  2. Budget: Has $28 maximum to spend
  3. Inequality: Cost must not exceed budget: 0.35k≤280.35k \leq 28

?�� Strategic Tip: "Per unit" means multiply the rate by the number of units to get total cost.

Choice B is incorrect because≥28\geq 28 would mean spending at least $28, exceeding the budget limit. Choice C is incorrect because it reverses the multiplication, putting budget as the coefficient. Choice D is incorrect because it adds kk and 0.35, which don't have compatible units (kWh vs dollars).

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