I think it's 11.56 minutes
1. Copper is very useful, so people want as much as possible.
2. We are running out, so we are extracting all the copper that we can to keep up with our needs.
A mineral found in a bridge is iron
It decreases in volume, as the energy is lost.
<span>Petrolyn motor oil is a combination of natural oil and synthetic oil.
</span><span>it contains 8 liters of natural oil for every 5 liters of synthetic oil.
</span>natural oil / synthetic oil
8 / 5
let x= liters of synthetic oil and
728-x = liters of natural oil
8/5 = 728-x/x , 8x = 5 (728-x)
8x = 3640-5x
8x+5x = 3640
13x = 3640
x = 280 litres
280 liters of synthetic oil is needed to make 728 liters of petrolyn oil.
