AbeNeedsAnswers wrote: ↑Sat May 16, 2020 7:19 pm
To rent a tractor, it costs a total of x dollars for the first 24 hours, plus y dollars per hour for each hour in excess of 24 hours. Which of the following represents the cost, in dollars, to rent a tractor for 36 hours?
A. x + 12y
B. x + 36y
C. 12x + y
D. 24x + 12y
E. 24x + 36y
A
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.
First, choose values for
x and
y
Let's say
x = 4 and
y = 3
In other words,
to rent a tractor, it costs a total of 4 dollars for the first 24 hours, plus 3 dollars per hour for each hour in excess of 24 hours. Which of the following represents the cost, in dollars, to rent a tractor for 36 hours?
TOTAL cost =
4 dollars (for the first time for hours) + (12)(
3 dollars) (for each of the 12 hours after the first 24 hours)
= 4 + 36
=
40 (dollars)
So, when
x = 4 and
y = 3, the answer to the question is
40 (dollars)
In other words, when we INPUT
x = 4 and
y = 3, the OUTPUT is
40
We'll now take each answer choice and plug-in
x = 4 and
y = 3.
The correct answer choice will be the one that evaluates to be
40
(A)
4 + 12(
3) =
40 Great!
(B)
4 + 36(
3) = 112. No good. We need an output of
40
(C) 12(
4) +
3 = 51. No good. We need an output of
40
(D) 24(
4) + 12(
3) = 132. No good. We need an output of
40
(E) 24(
4) + 36(
3) = 204. No good. We need an output of
40
Answer: A
Cheers,
Brent
