A triangular ABC cardboard with vertices labeled with letters A, B, and C is shown as in Figure 1. 3 ABC cardboards can be assembled on a flat surface as shown in Figure 2 by overlapping the A vertices and leaving no gaps between the edges and without the cardboards overlapping. The same process can be done using 9 ABC cardboards by overlapping the B vertices. Accordingly, using how many ABC cardboards can this process be done by overlapping the C vertices? A) 10 B) 12 C) 15 D) 18 E) 20
A triangular ABC cardboard with vertices labeled with letters A, B, and C is shown as in Figure 1. 3 ABC cardboards can be assembled on a flat surface as shown in Figure 2 by overlapping the A vertices and leaving no gaps between the edges and without the cardboards overlapping.
The same process can be done using 9 ABC cardboards by overlapping the B vertices.
Accordingly, using how many ABC cardboards can this process be done by overlapping the C vertices?\\
A) 10\\
B) 12\\
C) 15\\
D) 18\\
E) 20