Answer :
Since we have that 3395 represent the 70% of the total, we now want to know how much the 100% is, for that we do as follows:
First we multiply the total ammount we are given ($3395) times the percentage we want to know (100%) and divide by the percentage we are given (70%):
[tex]x=\frac{3395\cdot100}{60}\Rightarrow x=4850[/tex]x represents the original cost.
Originally since we have:
[tex]70->3395\text{ \& 100 }->x[/tex]Now we need to solve for x, and since we have that when 70 represents 3395, then, how much does 100 represent?
For that we multiply the percentage we want to know (100%) times the total ammount we are given ($3395) and divide by the percentage we are given that represents the total ammount (70%):
[tex]x=\frac{100\cdot3395}{70}=>x=4850[/tex]The basics go more or less like this:
If "a" represents "b", then "c" represents "d", is called "The rule of three", and with it you know that with 3 values you can infer the fourth on, as long as they are related in some way.
In the case of your problem, an ammount of money is represented by a percenage, and there is another percentage that is going to represent another ammount of money that we don't know. So we use this relationship to determine the ammount of money that the given percentage is representing.
[tex]a->b\text{ \& c}-d[/tex]Now if we have a, b & c, we can calculate d:
[tex]d=\frac{c\cdot b}{a}[/tex]And in the same fashion, as long as we have another set of 3 values we can determine the value of the fourth.