At Westonci.ca, we make it easy to get the answers you need from a community of informed and experienced contributors. Experience the convenience of finding accurate answers to your questions from knowledgeable professionals on our platform. Experience the ease of finding precise answers to your questions from a knowledgeable community of experts.

Find the number of permutations of n distinct things taken r together, in which 3 particular things must occur together.


.......
I have solution available but due to less explanation I am unable to understand so please provide PROPER EXPLANATION.

Spam/Palagrised answers will be reported, so please ignore if you don't know. Thanks!​​