6th Class Mental Ability Analytical Reasoning Analytical Reasoning

In this chapter, problems are based upon numbers of lines, triangles, squares and circles in a complex figure.

• To count number of lines, add all the numbers of horizontal, vertical and slanting lines.
• To count the number of triangles, add all the numbers of triangles formed by 1 component, 2 components, 3 components and so on.
• To count the number of circles, count all the centres of circles. 

EXAMPLE

How many triangles are there in the following figure?

(a) 14                            (b) 12                            (c) 10                            (d) 8

Explanation (b):

The figure may be labelled as shown below:

The triangles formed of 1 component are ABE, AEF, EFC, CED and BED.

The triangles formed of two components are ABF, ACE, BCE and ABD.

The triangles formed of three components are BFC and ACD.

There is only one triangle ABC formed of five components.

Thus, there are 5+4+2+1 =12 triangles in the figure.

Hence, the correct option is (b).