Question

A tree 33 m tall and 0.55 m in diameter at its base produces about 67000 L of oxygen per year. A person who exercises vigorously several hours a day might take in about 22 m of all per day. How many trees are needed to provide oxygen to 900 people breathing?

Answer 1

Person consumes $22m^3$ air per day=$0.2\times 22=4.4m^3\ O_2\\$

$\because\ air\ contains\ 20\ percentage \ of \ oxygen$

900 people will need $4.4\times 900=3960m^3\ O_2$ per day

total oxygen required per year = $3960\times 365=1445400m^3\ O_2$

Amount of Oxygen given by 1 tree per year = $67000\ l=67\ m^3$

Total no. of trees required = $\frac{1445400}{67}=21573.134$

So, nearly 21573 trees will be required.