Question

A stock closes at $71.80 on September 2nd. On September 3rd, the stock closed at

$80.10. What was the percentage change, to the nearest tenth?
Percentage Change =
11.6%
11.5%
9.2%
9.3%
Ending Price - Beginning Price
Beginning Price
x 100

Answer 1

well, the amount change is simply their difference, namely 80.10 - 71.80 = 8.3.

now, what's the percentage change from the 2nd to the 3rd? namely if we take 71.80 as the 100%, what is 8.3 off of it in percentage?

`\begin{array}{ccll} amount&\%\\ \cline{1-2} 71.80 & 100\\ 8.3& x \end{array} \implies \cfrac{71.80}{8.3}~~=~~\cfrac{100}{x} \\\\\\ 71.8x=830\implies x=\cfrac{830}{71.8}\implies x\approx 11.6`