If white is called black, black is called red, red is called yellow, yellow is called green, green is called blue, blue is called violet and violet is called orange, what would be the colour of human blood?

We may label the figure as shown.

The Simplest triangles are AFB, FEB, EBC, DEC, DFB and AFD i.e 6 in number.

The triangles composed of two components each are AEB, FBC, DFC, ADE, DBE and ABD i.e 6 in number.

The triangles composed of three components each are ADC and ABC i.e 2 in number.

There is only one triangle i.e DBC which is composed of four components.

Thus, there are 6 + 6 + 2 + 1 = 15 triangles in the figure