Carcass wrote:
It takes 1 pound of flour to make y cakes. The price of flour is w dollars for x pounds. In terms of w, x and y, what is the dollar cost of the flour required to make 1 cake?
A. \(\frac{xy}{w}\)
B. \(\frac{y}{wx}\)
C. \(\frac{w}{xy}\)
D. \(\frac{wx}{y}\)
E. \(wxy\)
These kinds of questions (Variables in the Answer Choices - VIACs) can be answered algebraically or using the INPUT-OUTPUT approach.
Let's use the INPUT-OUTPUT approach.
It takes 1 pound of flour to make y cakes. Let's let
y = 2, which means it takes 1 pound of flour to make
2 cakes.
So,
1 cake will require 0.5 pounds of flourThe price of flour is w dollars for x pounds.Let's let w = 6 and x = 2, which means flour costs 6 dollars for 2 pounds.
In other words,
flour costs 3 dollars per poundConclusion: If 1 cake will require 0.5 pounds of flour and flour costs 3 dollars per pound, then it will cost 1.5 dollars to make 1 cake.In other words, when y = 2, w = 6 and x = 2, the answer to the question is
1.5 dollars
From here, we'll INPUT y = 2, w = 6 and x = 2 into each answer choice to see which one yields an OUTPUT of
1.5 A. \(\frac{(2)(2)}{6}\) =
4/6 = 0.66666.... We need an output of
1.5. ELIMINATE A
B. \(\frac{2}{(6)(2)}\) =
1/6 = 0.16666.... We need an output of
1.5. ELIMINATE B
C. \(\frac{(6)}{(2)(2)}\) =
6/4 = 1.5. GREAT!
D. \(\frac{(6)(2)}{2}\) =
6. We need an output of
1.5. ELIMINATE D
E. \((6)(2)(2)\) =
24. We need an output of
1.5. ELIMINATE E
Answer: C