Question

For a carnival game, containers are arranged in a triangular display. The top row has 1 container. The second row has 2 container. the third row has 3 containers. The pattern continues until the bottom row, which has 10 containers. A contestant knocks down 29 containers on the first throw. How many containers remain?

Answer 1

For this, you will need to know the triangle numbers. To know how many are on row ten, find the cumulative frequency (running total) of every number up to ten

1 = 1
2 = 3
3 = 6
4 = 10
5 = 15
6 = 21
7 = 28
8 = 36
9 = 45
10 = 55

If there are 55 containers and 29 are knocked down, we do
55 - 29 = 26
26 containers remain

Answer 2

26 are left. Its just addition then subtraction.