Permutations And Combinations Question 256

Question: The sum of the digits in the unit place of all numbers formed with the help of 3, 4, 5, 6 taken all at a time is [Pb. CET 1990]

Options:

A) 18

B) 432

C) 108

D) 144

Show Answer

Answer:

Correct Answer: C

Solution:

  • Required sum $ =3\ !(3+4+5+6)=6\times 18=108 $ . [If we fix 3 of the unit place, other three digits can be arranged in $ 3\ ! $ ways similarly for 4, 5, 6.]



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