To answer this question we need to know how many liters of blood are pumped in a minute; we know the amount the heart pumps per heartbeat and how many times the heart beats in a minute, multyplying this quantities will lead to the amount of blood the heart pumps each minute:
[tex](7\times10^{-2})(72)=5.04[/tex]
Hence the heart pumps, in average, 5.04 liters per minute.
Now we need to determine how many minutes a year have. We know each year has 365 days, each day has 24 hours and each hour has 60 minutes, then a year has:
[tex]365\cdot24\cdot60=525600[/tex]
Hence, each year has 525,600 minutes.
With this information we can determine how many liters are pumped in a year; we just multiply the number of minutes in a year by the amount pumped in a minute:
[tex]5.04\cdot525600=2.65\times10^6[/tex]
Therefore, in 1 year, the heart pumps
[tex]2.65\times10^6[/tex]
liters of blood.
To determine how many liters the heart pumps in 70 years we multiply the amount we just found by 70:
[tex]2.65\times10^6\cdot70=1.85\times10^8[/tex]
Therefore, in 70 years, the heart pumps
[tex]1.85\times10^8[/tex]
liters of blood.
