Q55.The value of ∑20r=0 50−rC6 is equal to: (1) 51C7 −30C7 (2) 50C7 −30C7 (3) 50C6 −30C6 (4) 51C7 + 30C7
What This Question Tests
This question requires the application of combinatorial identities, specifically the hockey-stick identity (or a repeated application of Pascal's identity), to simplify a given summation of binomial coefficients.
Concepts Tested
Formulas Used
nCr + nC(r+1) = (n+1)C(r+1)
∑ (n+k)Ck = (n+k+1)C(k+1) (Hockey-stick identity, in a modified form)
📚 NCERT Sections This Tests
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5.15 Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory: (i) [Fe(CN)6] 4– (ii) [FeF6] 3– (iii) [Co(C2O4)3]3– (iv) [CoF6] 3–
13.5 — The Q Value Of A Nuclear Reaction A + B ® C + D Is Defined By
Physics Class 12 · Chapter 13
13.5 The Q value of a nuclear reaction A + b ® C + d is defined by Q = [ mA + mb – mC – md]c2 where the masses refer to the respective nuclei. Determine from the given data the Q-value of the following reactions and state whether the reactions are exothermic or endothermic. (i) 11 H+13 H →12 H+12 H (ii) 126 C+126 C →1020 Ne+ 24 He Atomic masses are given to be m ( 12 H ) = 2.014102 u m ( 13 H) = 3.016049 u m ( 126 C ) = 12.000000 u m ( 1020 Ne ) = 19.992439 u
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📋 Question Details
- Chapter
- Permutation & Combination
- Topic
- Combinatorial identities
- Year
- 2020
- Shift
- 04 Sep Shift 1
- Q Number
- Q55
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 7: Permutation & Combination
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