Merchant

The merchant lowered cost by 10% in December when it was not sold. Again, in January, it lowered costs by 20% and now costs 576 €.
A. How much did the goods stand originally?
B. How much do the goods cost after the first lowering?
C. How much percent of the total merchant lower cost?

Correct answer:

a =  800 EUR
b =  720 EUR
c =  28 %

Step-by-step explanation:

$$\begin{gathered} a\cdot (1-10/100)\cdot (1-20/100)=576 \\ 72a=57600 \\ a=\frac{57600}{72}=800 \\ a=800=800\text{EUR} \end{gathered}$$

$b=a\cdot (1-10/100)=800\cdot (1-10/100)=720\text{EUR}$

$c=100\cdot \frac{a-576}{a}=100\cdot \frac{800-576}{800}=28\%$

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