Permutation & Combination
Question
There are few letters, namely “GIIILK”.
- How many different ways the words can be arranged in a row?
- How many ways of arrangement that all three letters of “I” are together?
Answer
- 20
- 6
Permutation Formula
n!/(n-r)!
This formula calculates the number of permutations of n things taken r at a time
Combination Formula
n!/[(n-r)!r!]
This formula calculates the number of combinations of n things taken r at a time
Number of permutations of n things when there are n1, n2, …, nk repeated items.
n!/(n1!n2!…nk!)
About the Math Tutor - Dr Loo
I am a PhD holder with 9 years of teaching experience at secondary school and university. My expertizes are mathematics, statistics, econometrics, finance and machine learning.
Currently I do provide consultation and private tuition in Singapore. For those who are looking for math tutor in Singapore or statistics tutor in Singapore, please feel free to contact me at +65-85483705 (SMS/Whatsapp/Telegram).
Some of the math tuition in Singapore I provide includes O-level math tuition and also JC Math Tuition (H1 Math Tuition & H2 Math Tuition). On the other hand, my statistics tuition in Singapore mostly focus on pre-university level until postgraduate level. For those who prefer online tutoring service, the online O-level math tuition and online JC math tuition are also available.
For those who are looking for math tution in Singapore
Need help with this topic? I do provide mathematics home tuition in Singapore for O-level math and also JC H2 math. In addition, online math tutoring is available as well. Feel free to contact me if you would like to know further.
