Q67.If 2n+1P nโ1 : 2nโ1P n = 11 : 21 , then n2 + n + 15 is equal to :
What This Question Tests
The question tests the basic definition of permutations and the ability to solve a rational equation involving factorials to find the value of n, then compute a quadratic expression.
Concepts Tested
Formulas Used
nP_r = n! / (n-r)!
๐ NCERT Sections This Tests
1.3 โ Define The Following Terms:
Chemistry Class 11 ยท Chapter 1
1.3 Define the following terms: (i) Mole fraction (ii) Molality (iii) Molarity (iv) Mass percentage.
1.29 โ Nalorphene (C19H21No3), Similar To Morphine, Is Used To Combat Withdrawal
Chemistry Class 11 ยท Chapter 1
1.29 Nalorphene (C19H21NO3), similar to morphine, is used to combat withdrawal symptoms in narcotic users. Dose of nalorphene generally given is 1.5 mg. Calculate the mass of 1.5 ยด 10โ3 m aqueous solution required for the above dose.
1.4 โ Concentrated Nitric Acid Used In Laboratory Work Is 68% Nitric Acid By Mass In
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1.4 Concentrated nitric acid used in laboratory work is 68% nitric acid by mass in aqueous solution. What should be the molarity of such a sample of the acid if the density of the solution is 1.504 g mLโ1? 27 Solutions Reprint 2025-26
๐ Question Details
- Chapter
- Permutation & Combination
- Topic
- Permutations
- Year
- 2023
- Shift
- 31 Jan Shift 2
- Q Number
- Q67
- Type
- Numerical
- NCERT Ref
- Class 11 Mathematics Ch 7: Permutations and Combinations
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