Final answer:
To find the cost for four lessons, subtract the cost of 7 lessons from the cost of 11 lessons. Then, divide the result by 4 to find the cost per lesson. Multiply the cost per lesson by 4 to find the cost for four lessons.
Step-by-step explanation:
To find the cost for four lessons, we can determine the cost per lesson by finding the difference in cost between 11 lessons and 7 lessons. From the given information, 7 dance lessons cost $82 and 11 lessons cost $122.
The difference between the costs of 11 lessons and 7 lessons is $122 - $82 = $40.
So, the cost per lesson is $40 / 4 = $10. Therefore, the cost for four lessons is $10.