Find the time it takes for each spin to take place by dividing 5 minutes by 405 rotations:
[tex]\frac{5\min }{405\text{ rotations}}[/tex]Multiply that rate by 243 to find the time it takes for 243 rotations to take place:
[tex]\frac{5\min}{405\text{ rotations}}\times243\text{ rotations}=3\min [/tex]Therefore, it will take 3 minutes to go 243 rotations.
