Answer:
Tim read 81 pages.
Explanation:
If he read 3 pages on Monday and tripled the amount of pages he red based of off the amount of pages he read the previous day, he would have read 3 pages on Monday, 9 pages on Tuesday, 27 pages on Wednesday, and 81 pages on Thursday.
Monday: 3
Tuesday: 3 x 3 = 9
Wednesday: 9 x 3 = 27
Thursday: 27 x 3 = 81
I hope this helps you! :D