NDA2021MathematicsPermutation and CombinationActual
Suppose 20 distinct points are placed randomly on a circle. Which of the following statements is/are correct? 1. The number of straight lines that can be drawn by joining any two of these points is 380 . 2. The number of triangles that can be drawn by joining any three of these points is 1140 . Select the correct answer using the code given below.
Options
- A1 only
- B2 only
- CBoth 1 and 2
- DNeither 1 nor 2
Correct answer
B. 2 only
Step-by-step solution
Number of St lines = ²⁰ C ₂=190 Number of triangles = ²⁰ C ₃=1140