Question

Through research, scientists found a person consist of 3.2 x 10^-5 lbs of zinc. In the bodies of 3,500 such people, how much zinc is present.

Answer 1

One person has

$3.2x10^{-5}\text{ lbs of zinc}$

then, in the body of 3500 such people, there are

$3500\cdot3.2x10^{-5}\text{ lbs of zinc}$

this product is equal to

$3500\cdot(0.000032)=0.112\text{ lbs}$

of zinc