4
algebra

A social media influencer earns $150 per sponsored post minus a $45 platform fee per post. If they want to earn at least $420 this month, which inequality represents the minimum number of posts pp needed?

A

150p−45≥420150p - 45 \geq 420

B

150p−45p≥420150p - 45p \geq 420

C

(150−45)p≥420(150 - 45)p \geq 420

D

150−45p≥420150 - 45p \geq 420

Correct Answer: C

Choice C is the correct answer. Net earnings per post should be factored before multiplying by number of posts.

  1. Per-post earnings: $150 - $45 = $105 net per post
  2. Total for pp posts: 105p105p or equivalently (150−45)p(150-45)p
  3. Constraint: Want at least $420: (150−45)p≥420(150-45)p \geq 420

?�� Strategic Tip: When earnings and costs are per-unit, calculate net amount first, then multiply by quantity.

Choice A is incorrect because it subtracts $45 only once regardless of number of posts (should be $45 per post). Choice B is incorrect because it treats 45 as a coefficient of pp, but the fee is $45 total per post, not $45p. Choice D is incorrect because it has only one post earning $150, then subtracting a variable cost.

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Linear Functions Set 66