Just help. Also this question is related to question 5 so if you can do this one please help me with question 5

Answer:
55
Step-by-step explanation:
5th step = 15 timbers
6th step = 21 timbers
7th step = 28 timbers
8th step = 36 timbers
9th step = 45 timbers
10th step = 55 timbers
Hope this helps!!
Let me know if I'm wrong...