21
In how many ways 2 students can be chosen from the class of 20 students?
- A190
- B180
- C240
- D390
Correct answer: A
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0
CCommunity
190
NA
NA
0
CCommunity
Solution :
Formula : nCr = n! /(r!)(n - r)!
Here, n = 20 and r = 2
Number of ways in which 2 students can be chosen from a class of 20 students = 20C2
= 20! /(2!)(20 - 2)!
= 20! /(2!)(18)!
= (20 × 19)/ 2
= 10 × 19
= 190
2 students can be chosen in 190 different ways.
The correct option is A). 190
Formula : nCr = n! /(r!)(n - r)!
Here, n = 20 and r = 2
Number of ways in which 2 students can be chosen from a class of 20 students = 20C2
= 20! /(2!)(20 - 2)!
= 20! /(2!)(18)!
= (20 × 19)/ 2
= 10 × 19
= 190
2 students can be chosen in 190 different ways.
The correct option is A). 190