We know that the area doubles each week, that is, every 7 days.
The first area is 12.5 square meters. If this area in 7 days is 25 square meters, then how much would it be after 10 days.
[tex]\begin{gathered} x=10\text{days}\cdot\frac{25m^2}{7\text{days}}=\frac{250}{7}m^2 \\ x=35.7m^2 \end{gathered}[/tex]Hence, after 10 days it was spotted, the area was 35.7 square meters.
