Answer:
t=17.61 years.
Explanation:
Given that
Reserve of energy = 10,000 EJ
Energy used by human = 18 TW
We know that
[tex]1\ E= 10^{18}[/tex]
[tex]1\ T= 10^{12}[/tex]
So
[tex]Reserve\ of\ energy = 10,000 \times10^{18} J[/tex]
[tex]Reserve\ of\ energy = 10^{22} J[/tex]
[tex]Energy\ used\ by\ human = 18 \times10^{12}\ W[/tex]
Lets t time after energy will be exhaust
So
[tex]18 \times10^{12}\times t=10^{22}[/tex]
[tex]t=\dfrac{10^{22}}{18 \times10^{12}}\ s[/tex]
[tex]t=5.55\times 10^8 \ s[/tex]
We know that
1 year = 365 days
1 year = 365 x 24 hr
1 year = 365 x 24 x 3600 s
[tex]1year =3.15\times 10^7\ s[/tex]
So
[tex]t=\dfrac{5.55\times 10^8 }{3.15\times 10^7}[/tex]
t=17.61 years.