Hi there! So we are talking about the first plan being 17¢ per minute, but with no monthly fee. The other place has a fixed monthly fee of $18, but charges 12¢ per minute. To solve for the amount of minutes it would take for both plan to be equal, we can write and solve an equation. Set it up like this:
0.17m = 18 + 0.12m
This is because we are talking about $0.17 per minute for the first plan, and the second plan $0.12 per minute, with the fixed, one-time price of $18. The variable m stands for minutes. The amount goes up the more minutes you talk on the phone. First off, let's subtract 0.12m from both sides. 0.12m - 0.12m cancel each other out. 0.17m - 0.12m = 0.05m. The equation simplified is 0.05m = 18. Divide each side by 0.05 to isolate the m. 0.05m/0.05 cancel each other out. 18/0.05 is 360. We have a possible value of m. Let's substitute that number for m and see if it works. 360 * 0.17 is 61.2. 360 * 0.12 is 43.2. 43.2 + 18 is 61.2. 61.2 = 61.2. There. m = 360. It would take 360 minutes of calls for both plans to be equal.
