If someone smoked for 40 years and that reduced their life by 10 years, that 4:1 ratio translates to every 24 hours of being a smoker reducing lifespan by 6 hours (360 minutes). Assuming 40 cigarettes a day, that’s 360⁄40 or 9 minutes per cigarette, pretty close to the 11 given earlier.
I think there’s an error in your calculations.
If someone smoked for 40 years and that reduced their life by 10 years, that 4:1 ratio translates to every 24 hours of being a smoker reducing lifespan by 6 hours (360 minutes). Assuming 40 cigarettes a day, that’s 360⁄40 or 9 minutes per cigarette, pretty close to the 11 given earlier.