SAT Question 58ba7239: Percentages answer and explanation with Desmos solution

4$.It’sgiventhatthenumber$b$is$320 %$greaterthan＄160$. It follows that $b$ is equal to ＄160$plus$320 %$of$160$,whichcanbewrittenas$b = 160 + 3.2 ( 160 )$,or$b = 672$.It’salsogiventhatthenumber$a$is$55 %$lessthanthenumber$b$.Itfollowsthat$a$isequalto$b$minus$55 %$of$b$,whichcanbewrittenas$a = b - 0.55 b$,or$a = 0.45 b$.Substituting＄672$ for $b$ in this equation yields $a=0.45(672)$, or $a=302.4$. Note that 1512/5 and 302.4 are examples of ways to enter a correct answer.