Solve the problem.
-A collection of dimes is arranged in a triangular array with 12 coins in the base row, 11 in the next, 10 in the next, and so forth with 1 dime in the last row. Find the value of the collection.
A) $3.90
B) $15.60
C) $0.78
D) $7.80

Question

Quizplus · Accepted Answer

The total number of dimes is the sum of the first 12 natural numbers, which is calculated using the formula n(n + 1)/2, where n = 12. Thus, the total number of dimes is 12(12 + 1)/2 = 78. Since each dime is worth $0.10, the total value is 78 * $0.10 = $7.80.

Solve the Problem. -A Collection of Dimes Is Arranged in a Triangular Array