Question

Mankind has existed for about 10⁶ years whereas the universe is about 10¹⁰ year old. If the age of universe is taken to be one day, how many seconds has the mankind existed?

Answer 1

Since, 10¹⁰ years = 1 day 

10⁶ years = \(\frac{1}{10^{10}}\,\times\,10^6\,days\)

= 10^-4 days 

= 10^-4 × 24 × 60 × 60 s 

= 86400 × 10^-4 s 

= 8.64 sec.