Question

On a certain day, the exchange rate was 60 U.S. dollars for 50 euro. How many U.S. dollars were 70 euro worth that day? Show that your answer is reasonable.

Answer 1

60 / 50 = x / 70....60 U.S. to 50 euro = x U.S to 70 euro
cross multiply because this is a proportion
(50)(x) = (70)(60)
50x = 4200
x = 4200/50
x = 84 <== so 84 U.S dollars = 70 euros

proportions are nothing but equivalent fractions..
60/50 = 1.2
84/70 = 1.2
and as u can see, these are equivalent....so this is reasonable

Answer 2

the exchange rate is 60:50 (us:euro)

if you have 70 euros, then x:70

60(x) : 70(50)

60x /60 : 3500/60

x = 58.33

seventy euro dollars = $ 58.33 on that particular day


hope this helps