Chapter P - Prerequisites: Fundamental Concepts of Algebra - Exercise Set P.2 - Page 35: 146

Total heart beats in 80 years = 80$\times$365$\times$24$\times$60$\times$70 = 2.94336 $\times$ $10^{9}$

Heart beats per minute = 70 In 80 years = 80$\times$365 days = 80$\times$365$\times$24 hours = 80$\times$365$\times$24$\times$60 minutes Total heart beats in 80 years = 80$\times$365$\times$24$\times$60$\times$70 = 2.94336 $\times$ $10^{9}$