Markus painter

Markus used ¾ liter of paint to cover 10 ½ square meters of wall. How many liters of paint are needed to cover 12 ¼ square meters of the wall?

Correct answer:

V₂ =  7/8 l

Step-by-step explanation:

$$\begin{gathered} V_1=3/4=\frac{3}{4}=0.75\text{l} \\ {S}_1=10\frac{1}{2}=10+\frac{1}{2}=\frac{10\cdot 2+1}{2}=\frac{20+1}{2}=\frac{21}{2}=10.5{\text{m}}^2 \\ {S}_2=12\frac{1}{4}=12+\frac{1}{4}=\frac{12\cdot 4+1}{4}=\frac{48+1}{4}=\frac{49}{4}=12.25{\text{m}}^2 \\ {S}_1:V_1=S_2:V_2=const=\rho \\ {V}_2=V_1\cdot \frac{S_2}{S_1}=\frac{3}{4}\cdot \frac{\frac{49}{4}}{\frac{21}{2}}=\frac{7}{8}\text{l}=0.875\text{l} \end{gathered}$$

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