AMC 10 2023 Part B Problem 5

Maddy and Lara see a list of numbers written on a blackboard. Maddy adds 3 to each number in the list and finds that the sum of her new numbers is 45. Lara multiplies each number in the list by 3 and finds that the sum of her new numbers is also 45. How many numbers are written on the blackboard?

Answer Choices
A. 10
B. 5
C. 8
D. 6
E. 9