### PROBLEM LINK:

**Author:** Full name

### DIFFICULTY:

Very Easy

### PROBLEM:

Find whether N circularly linked gears can rotate simultaneously.

### QUICK EXPLANATION:

If N is odd the gears will be locked. If N is even they can rotate.

### EXPLANATION:

Consider two linked gears A and B. If A rotates clockwise B rotates anti clockwise and vice versa. For N circularly linked gears, the Nth gear’s rotation has to be opposite to that of the first gear. This is possible if N is even.

### AUTHOR’S SOLUTIONS:

Author’s solution can be found here.