Combinations & Permutations
The counting principle, arrangements with and without repeats, selections, and sharing objects out.
Problems
- Never Black with Blue
- At Least Two Digits Equal
- Five-Letter Palindromes
- At Most Two Different Digits
- Not with the Blue Hat
- Runs of Six
- Pass or Fail
- Below 700
- Odd Three-Digit Numbers
- Three Digits from 1 to 6
- Three Digits with a Zero
- Multiples of 5
- Between 3000 and 5000
- At Least One 6
- At Least Two Digits Alike
- Even Palindromes
- At Least One Banknote
- Tens Digit Not 2
- Divisible by 5, No Repeats
- Roads from A to D
- Not the Same Way Back
- The Forgotten Code
- Between 2000 and 6000
- At Most Three Digits in Base 5
- Below 500
- No Two Answers in a Row
- Even and Distinct
- Greater Than 350
- Odd, with a 4
- Divisible by 9
- Divisible by 4
- The 150th Number
- Big Squares in a Grid
- Digits from Two Sets
- Adding Every Two-Digit Number
- Decimals Above a Fraction
- Permutations That Use 3
- Three Friends Side by Side
- Keeping the Letters Apart
- Start with T, Don't End with N
- President, Then Vice-President
- A Factorial Equation
- Four People, Six Chairs
- Two Shelves of Books
- Keeping Subjects Together
- With 1, Without 2 and 3
- A Physics Book Between
- Only Nazmiye Between
- Girls Together, Boys Together
- At Both Ends of the Row
- Girls in Front
- 179 as a Block
- The 26th Number
- 2 Just Before 1
- Parents at Both Ends
- Where Does LKAEM Stand?
- Ahead in the Queue
- No Two Boys Together
- Alternating on the Shelf
- Seats in Two Rows
- Exactly Two in Between
- The Top-Left Photo
- From A to F
- Two Factorials, One Equation
- a and b Side by Side
- No Two Students Together
- Who Can Drive?
- One Player Between Them
- Zero Before Three
- Adding All the Numbers
- V Between S and Y
- Where Is 406?
- No Two Girls Together
- Digits Multiplying to 48
- The 55th Number
- Hundreds Digit on Top
- Gluing Numbers Together
- Exactly One Physics Book Between
- At Least Two in Between
- Rearranging 520033
- Order of the Goals
- Odds and Evens in Order
- Starting with F
- Rearranging 11224
- Pegs on a Line
- Every K Followed by I
- Lining Up by Height
- Vowels in Alphabetical Order
- Start with A, Don't End with K
- Rearranging 1001133
- Ending in 1
- Words from FİLİZ
- Even Rearrangements of 100223
- Only Two Fives Together
- Even Rearrangements of 1100022
- Emptying the Car Parks
- Two Courses at the Same Time
- Strictly Increasing Digits
- At Least One Even
- Pairs and Trips
- In Alphabetical Order
- Most of Row 7
- Choosing Two Hats
- Eleven Small Subsets
- At Least Six of Seven
- A Team of Three
- Exactly Two Girls
- Leaders Must Play
- A Group and Its Leader
- Threes and Sevens
- At Most Two Doctors
- A Committee and a Chair
- Two Already Chosen
- At Most Two Pass
- Handan and Aykut Together
- The First Five Are Compulsory
- Subsets Containing 2 and 3
- Lines Through Eight Points
- Six Circles Crossing
- Triangles on a Circle
- At Least Three Boys
- Products of Pairs
- From C(n, 3) to P(n, 3)
- Triangles from Seven Points
- When C(x, y) = 1
- Choose, Then Shelve
- P(n, 4) and C(n, n − 3)
- An Equation in C and P
- Two Binomials Make 70
- Permutations Meet Combinations
- Equal Binomial Coefficients
- From 140 to 3-Element Subsets
- Three Clashing Electives
- Three Cities, Five Travellers
- Three Vowels, Two Consonants
- At Least Three from the First Six
- Captains Already Known
- Murat and Handan Apart
- At Least One Couple
- Counting Rectangles
- Circle Points and Line Points
- Lines from Seven Points
- Triangles from Nine Points
- Eight Lines, Two Special Points
- Lines Through a Triangle's Points
- Which Groupings Are Right?
- Three Countries, Two Each
- A ≥ B > C
- Counting Quadrilaterals
- Three Toys, Four Siblings
- At Most One Toy Each
- Identical Balls, Different Boxes
- Letters into Postboxes
- Sums to Seven
- Eggs in Baskets
- At Least One Toy Each
- Sums to Eight
- Paying 95
- Five Pens, Three Children
- Reading TONYALI
- Through K or L
- Eggs in Every Basket
- Two Digits Nobody Picks
- Identical Boxes
- Avoiding One Street
- One or Two Boxes per Trip
- The Ant Avoids K, L and M
- Reading ARMUT
- Through B, Around the Closed Road
- The Fourth Term
- The x³ Term
- The Middle Term
- Finding a from a Term
- The Constant Term
- Two Middle Coefficients
- Reading a and b
- When the 4th Term Is Constant
- The y²/x⁴ Term
- Exponents Adding to 8
- Terms Containing z⁶
- Every Other Coefficient
- A Hidden Binomial
- A Trinomial Coefficient
- When Is There a Constant Term?
- Adding the Rational Terms
- Kaya's Seat Is Fixed
- Demir on Tuğba's Right
- Öykü or Aykut on the Right
- Parents Side by Side
- Couples Together
- Semra and Sinem Apart
- Glasses Together
- Facing Each Other
- Two Boys on Each Side
- No Two Girls Side by Side at the Table
- Doctors and Nurses Alternate
- Three Together, 720 Ways
- A Girl After Every Two Boys
- Keys on a Ring
- Choose, Then Seat Around a Table
- Mothers Between Their Children