Question

The weight of 10 identical samples of a substance is 0.1 pound. what is the weight of 1000 samples

Answer 1

The weight of 1000 samples is 10 pounds

Answer 2

$\bf \begin{array}{ccll} samples&lbs\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 10&0.1\\ 1000&x \end{array}\implies \cfrac{10}{1000}=\cfrac{0.1}{x}\implies x=\cfrac{1000\cdot 0.1}{10}$

you could also look at it this way, 1000 samples is really 10 * 100, or 100 times 10, if 10 weight 0.1, then 100 times that will just be 100 * 0.1.