In order to find the amount in dollars Sandra paid for the compact disk (CD) we have to use the Rule of three. This is a mathematical rule to find out an amount that is with another quantity given in the same relation as other two also known.
For example:
We already know 2,067 Colombian pesos is equivalent to $1 and that Sandra bought the CD for 31,005 Colombian pesos.
With this information we are able to stablish a relation between the Colombian pesos and the United States dollars, as follows:
2,067 Colombian pesos ----- $1
31,005 Colombian pesos -----X
And this is solved as follows:
[tex]X=\frac{(31005 Colombian pesos)(\$1)}{2067 Colombian pesos}[/tex]
Finally [tex]X=\$15[/tex]
Therefore, Sandra paid $15 for the CD.
