SAT Question 2e92cc21: Percentages answer and explanation with Desmos solution

87$.It’sgiventhatthenumber$a$is$110 %$greaterthanthenumber$b$.Itfollowsthat$a = \left( 1 + \frac{110}{100} \right) b$,or$a = 2.1 b$.It’salsogiventhatthenumber$b$is$90 %$lessthan＄47$. It follows that $b=\left(1-\frac{90}{100}\right)\left(47\right)$, or $b=0.1\left(47\right)$, which yields $b=4.7$. Substituting ＄4.7$for$b$intheequation$a = 2.1 b$yields$a = 2.1 \left( 4.7 \right)$,whichisequivalentto$a = 9.87$.Therefore,thevalueof$a$is$9.87$. Note that 9.87 and 9.870 are examples of ways to enter a correct answer.