Wool ball

Mrs. Black used 1.2 kg of wool to knit the sweater. The shop sold a wool ball weighing 100 grams for 39 CZK. How much money would she save if she knitted the sweater herself than if she bought it for CZK 720 in the shop? (CZK is Czech currency = Kč)

Final Answer:

x =  252 Kc

Step-by-step explanation:

$$\begin{gathered} S=720\text{Kc} \\ m=1.2\text{kg} \\ {m}_2=100\text{g}\to \text{kg}=100:1000\text{kg}=0.1\text{kg} \\ c=39\text{kc} \\ s=c\cdot m/m_2=39\cdot 1.2/0.1=468\text{Kc} \\ x=S-s=720-468=252\text{Kc} \end{gathered}$$

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