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Correct Option is 12

This can again be solved manually as well as using a scale diagram. 

Technique 1: (Manual) 

First point is at a distance of 1 cm, 2nd at 2 cm and so on – therefore, the distance of each point from the left edge of the scale will be 

1 st point – 1 cm 

2 nd – 3 cm 

3 rd – 6 cm 

4 th – 10 cm 

5 th – 15 cm 

6 th – 21 cm 

7 th – 28 cm 

8 th – 36 cm 

Similarily from the right edge too, the same story repeats. So we have totally 8+8 = 16 points. 

But, common points are to be counted as one and end points not to be counted. 

End points are the 8th point drawn from both the sides. So reduce 2 points from 16 which becomes 14. 

Now common points – so 5th point from the left; and 6th point from the right are common and will repeat twice. So they have to be counted only once. 

Reduce 2 more points from 14 which becomes 12 as the answer. 

Technique 2: (Using a scale - or diagram) 

Draw a rectangle 36 cm long with some width on the rough side of your notebook and mark 1 to 36 cm on it roughly. 

Start putting points on the top and bottom of the rectangle from both left and right hand sides. You will be easily able to see the total number of points as 16 and; out of which 2 points will be overlapping; and 2 as end points. So the final answer will be 12.

In the exam you can follow any of the above techniques. Both will take almost the same time. 

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