Plan A costs a total of $95 since it says $95 for unlimited talk and text.
Plan B: (.10 x 800) + (.05 x 1000) The (.10 x 800) represents 10 cents per talk minute for 800 minutes. The (.05 x 1000) represents 5 cents per text message for 1000 text messages. Solve: .10 x 800 = 80 .05 x 1000 = 50 80 + 50 = 130 This means Plan B will cost him $130 under these conditions.
Plan C: 20 + ((.05 x 800)+(.05 x 1000)) The 20 + represents a flat rate of $20 per month. The (.05 x 800) represents 5 cents per call minute. The (.05 x 1000) represents 5 cents per text. Solve: .05 x 800 = 40 .05 x 1000 = 50 20 + 40 + 50 = 110 This means Plan C will cost him $110 under these conditions.
Plan D: 45 + (.10(800 - 500)) The 45 + represents a flat monthly rate of $45. The (800 - 500) represents how many minutes he has to pay for with the 500 free. The .10 is the cost per extra minute. Solve: 800 - 500 = 300 .10 x 300 = 30 45 + 30 = 75 This means Plan D will cost him $75 under these conditions.
In short: Plan A- $95 Plan B- $130 Plan C- $110 Plan D- $75 The least expensive among these is Plan D, which only costs $75 per month.