This is Grade 6 MCOW 1 problem:

In this figure, how many triangles are there in it?

Answer: 35

Solution :

There are 7 types of triangles, and there are 5 of each type, so 7×5=35

Sources:

Photos taken from:

1. http://www.puzzles.com/puzzleplayground/CountingTriangles/CountingTriangles.htm

2. http://www.puzzles.com/puzzleplayground/CountingTriangles/CountingTrianglesSol.htm