Question

There are twenty students in Mr. Smith's class. He chooses two students randomly each day. How many ways can he choose two students?

Answer 1

• 190

Explanation:

This is the combination of 2 out of 20:

• 20C2 = 20!/18!2! = 20*19/2 = 190 ways

Answer 2

We have to find,

The number of ways in which he can choose two students.

Now the 2 out of 20 combination is,

→ 20C2

→ 20!/18!2!

→ 20 × 19/2

→ 10 × 19

→ 190 ways

Hence, there are 190 ways.