Question

1. elliot is choosing between two cell phone plans. plan a charges $10 each month plus $0.10 per text message. plan b charges $5 per month plus $0.20 per text message. which of the following inequalities can elliot use to find the number of text messages for which plan b is less expensive than plan a? a 10x + 0.1x < 5 + 0.2x b 10 + 0.1x > 5 + 0.2x c 10 + 0.1x < 5 + 0.2x d 0.1x + 5 > 0.2x + 10

Explanation:

Step1: Define cost functions

Let $x$ be the number of text - messages. Cost of Plan A, $C_A=10 + 0.1x$. Cost of Plan B, $C_B=5 + 0.2x$.

Step2: Set up the inequality

We want to find when Plan B is less expensive than Plan A, so $C_B5 + 0.2x$.

Answer:

B. $10 + 0.1x>5 + 0.2x$