Question

Margaret took a trip to Italy. She had to convert US dollars to euros to pay for her expenses there. At the time she was traveling, the conversion rate was represented by the function E(n)=0.72n, where n is the number of dollars and E(n) is the equivalent value in euros. Later, she traveled to Dubai and converted her remaining euros into the local currency, UAE dirhams. At that time, the conversion rate was represented by the function D(x)=5.10x, where x is the number of euros and D(x) is the equivalent value in dirhams. Which function can be used to convert n dollars directly to dirhams?
A) (D x E)(n) = 5.10(0.72n)
B) (D x E)(n) = (5.10x) x (0.72n)
C) (E x D)(n) = 0.72(5.10n)
D) (E x D)(n) = (0.72n) x (5.10x)

Answer 1

The conversion rate US dollars to Euros is represented with the function:
E(n)=0.72n
n- number of dollars
E(n) - Euros as a function of US dollars

The conversion rate Euros to Dirhams is :
D(x)=5.10x
x- number of Euros
D(x)- Dirhams as a function of Euros

We are trying to find D(x) in terms of n.
D(x) = 5.10x
x can be rewritten as E(n)
D(x) = 5.10(E(n))
D(x) = 5.10(E(n))
D(x) = 5.10(0.72n)
D(x) = 3.672n

According to this the following statement is true:
A) (D x E)(n) = 5.10(0.72n)