minutes left. If each costs $.50, then altogether that costs $2 more, for a total of
$6. Which answer choice yields $6? Answer choice D!
Plugging in is an essential tool for algebraic word problems. Here’s the rule
of thumb: If you see variables in the answer choice, you should plug in. It will
always work.
*Channel your inner seventh grader. Give in to the urge to plug-and-chug.
—Samantha
System of Equation Word Problems
Recently, the SAT has been unleashing word problems that translate into
multiple equation problems. You are likely to see two or even three of these in
the Math section. And while you totally can plug in, we find translating to be the
easier strategy. Take a look:
CanineCorp manufactures at least 75 RoboDogs per month. iLabs cost
$350 to manufacture, while E-huahuas cost $200. In the current
market, CanineCorp cannot afford to spend more than $25,000 in
manufacturing in a single month. If CanineCorp must make at least 15
iLabs and at least 20 E-huahuas per month, which of the following
systems of inequalities represents the conditions described, if x is the
number of iLabs and y is the number of E-huahuas?
A) 350y + 200x ≥ 25,000
x + y ≤ 75
x ≥ 15
y ≥ 20B) 350y + 200x ≤ 25,000
x + y ≥ 75
x ≤ 15
y ≤ 20C) 350x + 200y ≤ 25,000
x + y ≥ 75
x ≥ 15