1. Calculate the total mass of the solution:

* Mass of NaCl = 10 g

* Mass of H₂O = 100 g

* Total mass of solution = 10 g + 100 g = 110 g

2. Calculate the percent by weight:

* Percent by weight = (mass of solute / mass of solution) * 100%

* Percent by weight = (10 g / 110 g) * 100%

* Percent by weight ≈ 9.09%

Therefore, the percent by weight of the solution is approximately 9.09%.