Question

A pyramid of cans is on display in a supermarket. The row has 1 can, the second row has 2 cans, and the third row has 3 cans. If there are 10 rows, how many total cans were used to make the pyramid?

A. 45
B. 55
C. 65
D. 75

Answer 1

To find the total number of cans used to make the pyramid, you can use the formula for the sum of an arithmetic sequence. Hence the correct answer is option B

Step-by-step explanation:

To find the total number of cans used to make the pyramid, we need to sum up the number of cans in each row. The first row has 1 can, the second row has 2 cans, the third row has 3 cans, and so on. This is an arithmetic sequence with a common difference of 1. We can find the sum of this sequence using the formula: Sn = (n/2)(2a + (n-1)d), where Sn is the sum of the first n terms, a is the first term, and d is the common difference. In this case, n = 10, a = 1, and d = 1. Substituting the values into the formula, we get: Sn = (10/2)(2(1) + (10-1)(1)) = (10/2)(2 + 9) = 5(11) = 55.

Therefore, the total number of cans used to make the pyramid is 55. Answer choice B is correct.