Problem 3 · 2012 Math Kangaroo
Easy
Algebra & Patterns
off-by-onearithmetic-sequence
Father hangs towels on the washing line as shown in the picture. For three towels he uses 4 clothes pegs. How many clothes pegs would he use for 5 towels?
Show answer
Answer: C — 6
Show hints
Hint 1 of 2
Draw the towels in a row and mark a peg wherever two towels meet or a row ends.
Still stuck? Show hint 2 →
Hint 2 of 2
Each new towel adds just one extra peg, because neighbours share a peg.
Show solution
Approach: spot the 'one more peg than towels' pattern
- Three towels in a row need a peg at each end and one between each pair: 3 towels → 4 pegs.
- Every extra towel adds exactly one extra peg.
- So 5 towels need 5 + 1 = 6 pegs.
- The answer is 6.
Mark:
· log in to save