Percentages SAT question

Choice A is correct. The result of increasing a positive quantity $w$ by $x\%$ can be represented by the expression $(1+\frac{x}{100})w$. Therefore, the result of increasing a positive quantity $w$ by $43\%$ can be found by substituting $43$ for $x$ in the expression $(1+\frac{x}{100})w$, which gives $(1+\frac{43}{100})w$, or $1.43w$. Thus, the expression $1.43w$ represents the result of increasing a positive quantity $w$ by $43\%$.

Choice B is incorrect. This is the result of decreasing a positive quantity $w$ by $43\%$.

Choice C is incorrect. This is the result of increasing a positive quantity $w$ by $4,200\%$.

Choice D is incorrect. This is the result of decreasing a positive quantity $w$ by $57\%$.