heart rate at 80 beats a minute. how many days will it take his heart to beat 1,000,000 times?

Question

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? Show your work and be sure you explain each step.

Answer 1

To convert the units without changing the value, we use the multiplicative identity (that is, 1).  Multiply a value by 1 and it stays the same.

 

For this problem, we know:

    1 = (1 hr) / (60 min)

    1 = (1 day) / (24 hr)

    1 = ( (80 beats)/(1 min) ) = ( (1 min)/(80 beats) )      [choose the one we need]

 

We have:

   1,000,000 beats

   (1000000 beats) * 1

   (1000000 beats) * ( (1 day) / (24 hr) ) * ( (1 hr) / (60 min) ) * ( (1 min) / (80 beats) )

   (1000000)*(1/24)*(1/60)*(1/80) days      [note: hr, min, beats cancel out]

   8.68 days