COMEDK · Maths · 4. Permutation Combination
There are 10 points in a plane out of which 4 points are collinear. How many straight lines can be drawn by joining any two of them?
- A 45
- B 39
- C 21
- D 40
Answer & Solution
Correct Answer
(D) 40
Step-by-step Solution
Detailed explanation
The total number of ways to select 2 points out of 10 points is given by \(^{10}C_{2}\). \(^{10}C_{2} = \dfrac{10 \times 9}{2 \times 1} = 45\). Since 4 points are collinear, joining any two of these 4 points results in the same line. The number of ways to select 2 points from…
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