Answer
33 messages
Work Step by Step
Step 1) .15 x t ... Let t be the total number of text messages sent/received. 15 cents for each text message = .15 cents times t is the total amount spent on text msgs.
Step 2) 399.99 + .15t ≤ 45 ... The Basic plan plus money spent on text messages should be less than or at most 45
Step 3) .15t ≤ 5.01 ... Subtract 39.99 from both sides
Step 4) t ≤ 5.01 ÷ .15 ... Divide by .15 on both sides to get t alone
Step 5) t ≤ 33.4 ... Simplify
Step 6) 33 messages ... Rounded final answer
