Question

How many years would it take to spend Avogadro's number of rupees at the rate of 10 lakh rupees per second? $\text{(M.L.N.R. Allahabad 1990)}$

Answer 1

$\frac{6\cdot 02\ast {10}^{23}}{1000000}s=6\cdot 02\ast {10}^{17}s$
$=\frac{6\cdot 02\ast {10}^{17}}{60\ast 60\ast 24\ast 365}=1\cdot 9089\ast {10}^{10}years$