There is a stack of plates in the backyard. There are 4 plates in the 1st layer, 8 in the second, 16 in the third, 32 in the fourth, and so on. There are total 10 rows/layers. How many total plates are in the stack?

Respuesta :

Given that

[tex]\begin{gathered} layer1=4plates \\ layer2=8plates \\ layer3=16plates \\ layer4=32plates \end{gathered}[/tex]

Explanation

From the above, it is easy to see that the arrangement of the layers follows a geometric sequence where

[tex]\begin{gathered} first\text{ term = 4} \\ common\text{ ratio = }\frac{second\text{ }term}{first\text{ term}}=\frac{8}{4}=2 \end{gathered}[/tex]

Since r>1, therefore the sum of 10 terms, which implies would give the total number of plates that are in the stack can be seen below.

[tex]\begin{gathered} S_n=\frac{a(r^n-1)}{r-1} \\ therefore; \\ S_{10}=\frac{4(2^{10}-1)}{2-1}=\frac{4(1024-1)}{1}=4(1023)=4092 \end{gathered}[/tex]

Answer: 4092