Pedro exceeded the plan in the months of February and April. His additional cost in the 6 months was $14.00.
Explanation:
Step 1; Pedro's service offers up to 5 ringtones for free so first, we need to identify which months Pedro downloaded for than 5 ringtones. In January, March, May and June he downloaded 5 or lesser than 5 ringtones. In the months of February, and April, he exceeded the prescribed limit on downloads.
Step 2; Each additional ringtone costs $3.50 each. In February, Pedro downloaded 6 ringtones and in April he downloaded 8 ringtones.
The additional cost in February = (6 - 5) × $3.50 = 1 × $3.50 = $3.50.
The additional cost in April = (8 - 5) × $3.50 = 3 × $3.50 = $10.50.
Total additional cost = The additional cost in February + The additional cost in April = $3.50 + $10.50 = $14.00