Question

In how many ways 2 students can be chosen from the class of 20 students?

Answer 1

Step-by-step explanation:

In how many ways 2 students can be chosen from the class of 20 students?

There are 10*9 = 90 different ways (assuming order matters). If order does not matter, then there are 90/2 = 45 different ways.

Answer 2

Answer:

The number of ways of selecting 20 students from a class of 20 students is 190.

Step-by-step explanation:

Given,

There are n = 20 students in the class.

To find,

The no. of ways in which 2 students can be chosen from the class of 20 students.

Calculation,

If there are n things and we are wishing to select x number of possibilities from the n things then the number of possible ways are:

ⁿCₓ = n!/(n - x)! (x!)

Hence, here n = 20, x = 2

And we are wishing to find the number of possibilities for selecting 2 students from 20 students.

i.e.

No. of possibilities = ²⁰C₂ = 20!/(20 - 2)! (2!)

²⁰C₂ = (20 × 19)/2

⇒ ²⁰C₂ = 190.

Therefore, the number of ways of selecting 20 students from a class of 20 students is 190.

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