Question

a side of an apartment building is shaped like a steep staircase. the windows are arranged in columns. the first column has 3 windows, the next has 6, then 12 and so on. how many windows are on the side of the apartment building if it had 10 columns

Answer 1

3069 windows on the side of the apartment building if it has 10 columns.

Explanation:

We can notice that the number of windows in each column is double the number of windows in the previous column. So, we can write down the number of windows in each column as a sequence of powers of 2:

3, 6, 12, 24, 48, 96, 192, 384, 768, 1536

We can see that this is a geometric sequence with a common ratio of 2. We can use the formula for the sum of a geometric sequence to find the total number of windows:

Sn = a(1 - r^n)/(1 - r)

where

a = 3 (the first term)

r = 2 (the common ratio)

n = 10 (the number of terms we want to sum)

Substituting these values into the formula, we get:

Sn = 3(1 - 2^10)/(1 - 2)

= 3(1 - 1024)/(-1)

= 3(1023)

= 3069

Therefore, there are 3069 windows on the side of the apartment building if it has 10 columns.