Answer:
a)360 blocks are placed in rows
b)There are in the top row.
Explanation:
From the question, we can deducted that there is decrease in the number of rows by 1 from 30 to some number of rows .
Let denote the number of rows as 'n'
Given:
Sn = 360
a = 30
d = -1.
To calculate Sn, we will make use of formula below;
Sn = n/2 (2a + (n - 1)d )
CHECK THE ATTACHMENT FOR DETAILED EXPLANATION
