Question

A toy stores percent of markup is 30%. A model train costs the store $80. Find the markup.

Answer 1

If we take 80 to be the 100%, what is 30% off of that anyway?

$\bf \begin{array}{ccll} amount&\%\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 80&100\\ x&30 \end{array}\implies \cfrac{80}{x}=\cfrac{100}{30}\implies \cfrac{80\cdot 30}{100}=x$

so the markup amount is "x".

Answer 2

1. We assume, that the number 80 is 100% - because it's the output value of the task.

2. We assume, that x is the value we are looking for.

3. If 80 is 100%, so we can write it down as 80=100%.

4. We know, that x is 30% of the output value, so we can write it down as x=30%.

5. Now we have two simple equations:

1) 80=100%

2) x=30%

where left sides of both of them have the same units, and both right sides have the same units, so we can do something like that:

80/x=100%/30%

6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for what is 30% of 80

80/x=100/30

(80/x)*x=(100/30)*x       - we multiply both sides of the equation by x

80=3.33333333333*x       - we divide both sides of the equation by (3.33333333333) to get x

80/3.33333333333=x

24=x

x=24

now we have:

30% of 80=24