how many lines can be drawn from 10 points out of which 4 points are collinear?
Asked by Jaahnvi
| 9th Jun, 2013,
02:46: PM
Expert Answer:
Straight line can be formed by joining 2 points
so number of ways in which we can select 2 points from 10 points is = 10C2
but it also include that in which 4 points are in straight line . from those 4 points only one line can be formed .
so we have to subtract 4C2 -1 from above result
Therefore, total number of lines = 10C2 - 4C2 + 1 = 45 - 6 + 1 = 40
Straight line can be formed by joining 2 points
so number of ways in which we can select 2 points from 10 points is = 10C2
but it also include that in which 4 points are in straight line . from those 4 points only one line can be formed .
so we have to subtract 4C2 -1 from above result
Therefore, total number of lines = 10C2 - 4C2 + 1 = 45 - 6 + 1 = 40
Answered by
| 9th Jun, 2013,
02:53: PM
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