## Elementary Algebra

Let X represent the amount of Euros a traveler could get for 300 dollars. The exchange rate is 4 Euros for 5 United States dollars, or $\frac{4}{5}$. Now, let’s set up a proportion with the ratio given and a ratio which compares the amount of Euros to the amount of dollars. So, $\frac{4}{5}$ = $\frac{X}{300}$ To solve this equation, we equate the cross products. 4 $\times$ 300 =5 $\times$ X 1200 = 5X Divide both sides by 5. X = 240 A traveler would get 240 Euros for 300 US dollars.