Final answer:
The difference between the 3rd and 10th terms of the sequence with the formula a_n = 3n + 11 is 21.
Step-by-step explanation:
The student is asking to find the difference between the 3rd and 10th terms in the arithmetic sequence given by the formula an = 3n + 11. To find the 3rd term, substitute n = 3 into the formula to get a3 = 3(3) + 11 = 20.
To find the 10th term, substitute n = 10 into the formula to get a10 = 3(10) + 11 = 41.
The difference between the 10th and 3rd terms is 41 - 20 = 21.