In this problem we can calculate the sand amound in each of the elements of the mixture.
1) for the first one: 2m^2 with 35% of sand:
[tex]\begin{gathered} 2\to100 \\ x\to35 \end{gathered}[/tex]solving the rule of 3 is going to be:
[tex]x=\frac{2\times35}{100}=0.7m^2[/tex]so in the first element we have 0.7 m^2 of sand
2) For the seconf: 6m^2 with the 15% of sand:
[tex]\begin{gathered} 6\to100 \\ x\to15 \end{gathered}[/tex]Solving the rule of 3 is going to be:
[tex]x=\frac{6\times15}{100}=0.9m^2\text{ }[/tex]so in the second element we have 0.9 m^2 of sand
So in total the content of sand is:
[tex]0.7+0.9=1.8m^2[/tex]