Question:
Simplify $\frac{\sqrt{40\cdot9}}{\sqrt{49}}$.

Answer:
Factoring the squares out of $40\cdot9$ gives us $2^2\cdot3^2\cdot10 = 6^2\cdot10$.  Thus, the numerator is $6\sqrt{10}$.

The denominator is $7$, because $7^2=49$.  So our answer is $\boxed{\frac{6\sqrt{10}}{7}}$.