Tracksuits

There are 250 tracksuits in a box. The shop sold 1/5 of the tracksuits on Monday, 1/10 on Tuesday, 2/5 on Wednesday, and the rest on Thursday. How many tracksuits did the shop sell on Thursday?

Correct answer:

x =  75

Step-by-step explanation:

$$\begin{gathered} a=\frac{1}{5}+\frac{1}{10}+\frac{2}{5}=\frac{2}{10}+\frac{1}{10}+\frac{4}{10}=\frac{2+1+4}{10}=\frac{7}{10}=0.7 \\ b=1-a=1-\frac{7}{10}=\frac{1\cdot 10}{10}-\frac{7}{10}=\frac{10}{10}-\frac{7}{10}=\frac{10-7}{10}=\frac{3}{10}=0.3 \\ x=250\cdot b=250\cdot \frac{3}{10}=\frac{250\cdot 3}{10}=\frac{750}{10}=75 \end{gathered}$$

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