Formulas Quiz - CBSE Class 11 Mathematics

Free practice quiz: Formulas (CBSE Class 11 Mathematics). 12 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

Sample questions

1. What is the formula for permutations of n objects taken r at a time?

   1. n!/(n-r)!
   2. n!/r!(n-r)!
   3. n!r!
   4. r!/n!(n-r)!
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   Answer: A. n!/(n-r)!

   The formula for permutations is n!/(n-r)!, where n is the total number of objects and r is the number of objects taken at a time.

2. If n = 5 and r = 2, what is ⁵P₂?

   1. 10
   2. 20
   3. 120
   4. 60
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   Answer: B. 20

   ⁵P₂ = 5!/(5-2)! = 5!/3! = (5*4*3*2*1)/(3*2*1) = 20

3. How many ways can you arrange 4 books on a shelf?

   1. 4
   2. 12
   3. 24
   4. 16
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   Answer: C. 24

   This is a permutation problem. 4! = 4 * 3 * 2 * 1 = 24

4. Simplify: (n+1)!/n!

   1. n+1
   2. n
   3. 1
   4. n+2
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   Answer: A. n+1

   (n+1)! = (n+1) * n!, so (n+1)!/n! = n+1

5. A bag contains 5 red and 3 blue balls. How many ways can you select 2 red and 1 blue ball?

   1. 30
   2. 15
   3. 60
   4. 10
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   Answer: A. 30

   ⁵C₂ * ³C₁ = 10 * 3 = 30

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