Sylvester measured his pulse and found that his heart beat at a rate of 80 beats a minute at rest. at this rate how many days will it take his heart to beat 1,000,000 times?

Firstly you calculate how many minutes it takes for a heart to beat 1 million times:
1,000,000 / 80 = 12,500 minutes

Secondly, how many are there minutes in a day:
 24 hours  × 60 minutes in an hour = 1,440 minutes in a day

Thirdly you divide a total number of minutes needed with a number of minutes per day:

12,500 / 1,440 = 8.680[5] or 8 whole days + 49/72 of a day 

Then you multiply 49 with 24 (number of hours) and divide by 72
49×24/72 = 16.[3] which gives us a total of 8 days 16 hours and 1/3 of an hour e.g.: 8 days 16 hours and 20 minutes