Soccer field distance

The soccer player circled the field in a rectangle seven times. He walked 840 meters. How long are the sides of the course if one side is 20 meters longer than the other?

Final Answer:

a =  40 m
b =  20 m

Step-by-step explanation:

$$\begin{gathered} 2\cdot (a+b)=840/7 \\ a=20+b \\ a+b=840/14 \\ (20+b)+b=840/14 \\ 28b=560 \\ b=\frac{560}{28}=20 \\ b=20 \\ a=20+b=20+20=40\text{m} \end{gathered}$$

$b=20=20\text{m}$

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