On average, each cigarette a person smokes takes 8 minutes off that person's life span. if someone smokes 20 cigarette per day for 35 years, how much will smoking shorten the person's life? (round you answer to the nearest year.)

(8 min) x ( day/1,440 min) x (20 /day) x (365 da/yr) x (35 yr)  = 

      (8 x 20 x 365 x 35) / (1,440)  days =

                (2,044,000) / (1,440)  days =

                             1,419-4/9  days  =  3.89 years

            Rounded to the nearest year:  4 years

At a pack a day for 35years, I would have expected more than
4 years' damage.  But I've checked my math and haven't found
the mistake, so I'll let that be my answer.