A single tree produces about 2.6 × 10² lb of oxygen each year. The Amazon rainforest has about 3.9×
t/?f=%2010%5E%7B11%7D%20" id="TexFormula1" title=" 10^{11} " alt=" 10^{11} " align="absmiddle" class="latex-formula"> trees. About how many pounds of oxygen are produced in the rainforest each day ?
The answer is 165 because you take 66 and multiply it by .40 and you end up with 165. (.40 because percent means of one hundred so you make 40 to .40 )