Question

A stack of logs has 32 logs on the bottom layer. Each subsequent layer has 6 fewer logs than the previous layer. If the top layer has two​ logs, how many total logs are there in the​ pile?

Answer 1

Answer:  The total number of logs in the pile is 6.

Step-by-step explanation:  Given that a stack of logs has 32 logs on the bottom layer. Each subsequent layer has 6 fewer logs than the previous layer and the top layer has two​ logs.

We are to find the total number of logs in the pile.

Let n represents the total number of logs in the pile.

Since each subsequent layer has 6 fewer logs then the previous layer, so the number of logs in each layer will become an ARITHMETIC sequence with

first term, a = 32  and  common difference, d = -6.

We know that

the n-th term of an arithmetic sequence with first term a and common difference d is

$a_n=a+(n-10)d.$

Since there are n logs in the pile, so we get

$a+(n-1)d=2\\\\\Rightarrow 32+(n-1)(-6)=2\\\\\Rightarrow 32-6n+6=2\\\\\Rightarrow 6n=36\\\\\Rightarrow n=6.$

Thus, the total number of logs in the pile is 6.