There are 10 stones numbered from 1 to 10. A fly visits stones in the…
2024
There are 10 stones numbered from 1 to 10.
A fly visits stones in the following repeating order, one position per minute:
5, 9, 3, 7, 1, 5, 9, 3, 7, 1, ...
On which stone will the fly be at the end of 60 minutes?
- A.
1
- B.
5
- C.
6
- D.
8
Attempted by 1180 students.
Show answer & explanation
Correct answer: A
Key idea: the fly visits stones in a repeating 5-step cycle.
Step 1: Write the cycle of stones visited each minute: 5, 9, 3, 7, 1. After minute 5 the pattern repeats.
Step 2: Find where minute 60 falls in the 5-step cycle. Compute 60 mod 5 = 0, which means minute 60 corresponds to the 5th element of the cycle.
Step 3: The 5th element of the cycle is 1, so at the end of 60 minutes the fly is on stone 1.
Answer: 1