Problem 1 · Spot and count repeating groups · 3 points
Made by AI and not reviewed by a real person.
Lia strings beads in a repeating pattern: red, blue, blue, red, blue, blue, red, blue, blue, … How many blue beads are in her first 11 beads?
- 6
- 5
- 7
- 4
- 8
Show a hint
- Find the smallest group that starts over. How many times does it fit before bead 11?
- Remember to count any beads left after the complete groups.
Show the answer and solution
Answer: C — 7
The group red, blue, blue repeats. Three groups make 9 beads with 6 blue beads. Beads 10 and 11 are red and blue, so there are 7 blue beads altogether. The tempting answer 6 forgets to count the blue bead at position 11.