Problem 7 · 2017 Math Kangaroo
Medium
Spatial & Visual Reasoning
transformationssequence-of-figures
Alfred turns his building block 10 times. The first three times can be seen in the picture. What is the final position of the building block? (The five positions are shown as choices A, B, C, D, E.)
Show answer
Answer: D
Show hints
Hint 1 of 2
Look at the first three pictures and notice that every turn is the same little turn.
Still stuck? Show hint 2 →
Hint 2 of 2
The block goes back to looking the same after a few turns, so find that repeat and see where turn 10 lands.
Show solution
Approach: follow the repeating turn up to turn 10
- Each turn is the same. After it keeps turning, the block comes back to the very first picture every 4 turns.
- Count by fours: turn 4 and turn 8 both look like the start.
- Two more turns after turn 8 (turn 9, then turn 10) match the second and third pictures.
- So at turn 10 the block looks like option D.
Mark:
· log in to save