Answer: 120
Step-by-step explanation: To solve this problem, we can translate this question into an equation. We can write 35% as the decimal .35, "of what number" means multiply "is 42" = 42.
(.35) (x) = 42
Now to solve for x, we divide both sides of the equation by .35. On the left, the .35's cancel out and we are left with x. On the right, we have 42 divided by .35 = 120. Therefore, 35% of 120 is 42.