Question

In how many ways a group of 3 students has formed from a three classes, number of students in class VI, VII and VII are 24, 36 and 20. Ensure that one student in a group from each class.

1. 12451
2. 23412
3. 17280
4. 12675
5. 23432

Answer 1

Correct Answer - Option 3 : 17280

Given

Number of student in class VI = 24

Number of students in class VII = 36

Number of students in class VIII = 20

Calculation:

Number of ways a group of 3 Students formed from each class ensure that one student from each class = ²⁴C₁  × ³⁶C₁  × ²⁰C₁

⇒ ²⁴C₁  × ³⁶C₁  × ²⁰C₁ = 17280