[tex]\begin{gathered} A=red\text{ pencils = 6} \\ P(A)=\frac{2}{7} \\ x=\text{ }no\text{ red pencils} \\ \text{total penceils = A+x} \\ \text{Hence} \\ \frac{2}{7}=\frac{6}{6+x} \\ \text{Solving x} \\ (2)(6+x)=(7)(6) \\ 12+2x=42 \\ 2x=42-12 \\ 2x=30 \\ x=\frac{30}{2} \\ x=\text{ 15} \\ \text{There are 15 no red pencils in the box} \end{gathered}[/tex]
