Koos spent

Koos spent 3/7 of his monthly pocket money during the first week. The following week he spends two-thirds of what he spent the previous week. The fraction of the pocket money that is still left?

Correct answer:

x =  2/7

Step-by-step explanation:

$$\begin{gathered} a=\frac{3}{7}\doteq 0.4286 \\ b=\frac{2}{3}\cdot a=\frac{2}{3}\cdot \frac{3}{7}=\frac{2\cdot 3}{3\cdot 7}=\frac{6}{21}=\frac{2}{7}\doteq 0.2857 \\ x=1-a-b=1-\frac{3}{7}-\frac{2}{7}=\frac{2}{7}=0.2857 \end{gathered}$$

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