Permutations And Combinations Question 135

Question: In how many ways can 6 persons be selected from 4 officers and 8 constables, if at least one officer is to be included [Roorkee 1985; MP PET 2001]

Options:

A) 224

B) 672

C) 896

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

  • Required number of ways $ {{=}^{4}}C_1{{\times }^{8}}C_5{{+}^{4}}C_2{{\times }^{8}}C_4{{+}^{4}}C_3{{\times }^{8}}C_3{{+}^{4}}C_4{{\times }^{8}}C_2 $ $ =4\times 56+6\times 70+4\times 56+1\times 28=896 $ .



sathee Ask SATHEE

Welcome to SATHEE !
Select from 'Menu' to explore our services, or ask SATHEE to get started. Let's embark on this journey of growth together! 🌐📚🚀🎓

I'm relatively new and can sometimes make mistakes.
If you notice any error, such as an incorrect solution, please use the thumbs down icon to aid my learning.
To begin your journey now, click on

Please select your preferred language
कृपया अपनी पसंदीदा भाषा चुनें