# How do you calculate the number of cans in this arithmetic progression?

##
Cans are arranged in a pile such that each row has one less can than the row below. There is a total of 3240 cans in the pile. How many cans are there in the bottom row?

Cans are arranged in a pile such that each row has one less can than the row below. There is a total of 3240 cans in the pile. How many cans are there in the bottom row?

##### 1 Answer

Jan 5, 2018

#### Explanation:

If there is one can in the top row and there are

#1/2 n (n+1)#

So let's try to solve:

#3240 = 1/2 n(n+1)#

Multiply both sides by

#6480 = n(n+1)#

Note that

So there are