Q72.An urn contains 5 red marbles, 4 black marbles and 3 white marbles. Then, the number of ways in which 4 marbles can be drawn so that at the most three of them are red is ___________.
What This Question Tests
The problem asks for the number of ways to draw marbles with a constraint ('at most three of them are red'), which can be solved by considering complementary counting or by summing valid cases.
Concepts Tested
Formulas Used
โฟCแตฃ = n! / (r!(n-r)!)
๐ NCERT Sections This Tests
5.12 โ Write All The Geometrical Isomers Of [Pt(Nh3)(Br)(Cl)(Py)] And How Many Of
Chemistry Class 11 ยท Chapter 5
5.12 Write all the geometrical isomers of [Pt(NH3)(Br)(Cl)(py)] and how many of these will exhibit optical isomers?
5.11 โ Draw All The Isomers (Geometrical And Optical) Of:
Chemistry Class 11 ยท Chapter 5
5.11 Draw all the isomers (geometrical and optical) of: (i) [CoCl2(en)2] + (ii) [Co(NH3)Cl(en)2] 2+ (iii) [Co(NH3)2Cl2(en)]+
12.5 โ A Hydrogen Atom Initially In The Ground Level Absorbs A Photon,
Physics Class 12 ยท Chapter 12
12.5 A hydrogen atom initially in the ground level absorbs a photon, which excites it to the n = 4 level. Determine the wavelength and frequency of photon.
๐ Question Details
- Chapter
- Permutation & Combination
- Topic
- Combinations with constraints
- Year
- 2020
- Shift
- 08 Jan Shift 1
- Q Number
- Q72
- Type
- Numerical
- NCERT Ref
- Class 11 Mathematics Ch 7: Permutations and Combinations
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