Answer
$2.28\times10^{9}$
Work Step by Step
We can find the average lifespan of a human = 72.35 yrs.
We know that, $1\space yr = 365\times24\times60\times60\space s$
$\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space = 31536\times10^{3} s$
By using the above conversion factor, we can write,
Average lifespan of a human $= 72.35\space yr \times 31356\times10^{3}\space \frac{s}{yr}$
$\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space = 2.28\times10^{9}\space s\space-(1)$
Human heart beat $=1\space s\space -(2)$
$(1)\div(2)=\gt$
Number of heartbeats in typical
human lifetime$\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space= \frac{2.28\times10^{9}\space s}{1\space s}$
$\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space\space = 2.28\times10^{9}$
