A renewable energy research laboratory tested four experimental photovoltaic panel coating… — GMAT

A renewable energy research laboratory tested four experimental photovoltaic panel coatings (Coating Alpha, Coating Beta, Coating Gamma, and Coating Delta) across three sunlight intensity levels (Low, Medium, and High). The table below displays the measured power output, in watts per square meter ( $\text{W/m}^2$ ), for each coating under each sunlight intensity level:

Coating	Low Intensity	Medium Intensity	High Intensity
Coating Alpha	80	180	280
Coating Beta	90	195	310
Coating Gamma	75	170	$x$
Coating Delta	$y$	200	320

What is the average (arithmetic mean) power output of Coating Gamma across all three sunlight intensity levels?

(1) Under High Intensity, the power output of Coating Gamma is 10% greater than the power output of Coating Alpha under High Intensity.

(2) The average (arithmetic mean) power output of Coating Delta across the three intensity levels is equal to the average (arithmetic mean) power output of Coating Beta across the three intensity levels.

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.Answer
B
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D
EACH statement ALONE is sufficient.
E
Statements (1) and (2) TOGETHER are NOT sufficient.

Answer

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

Rephrasing the question target shows that finding the average power output of Coating Gamma requires finding the unknown value

x

. Statement (1) directly gives a percentage relationship between

x

and Coating Alpha's high-intensity output (

280 \text{ W/m}^2

), allowing us to calculate

x = 308

and thus the exact mean. Statement (2) allows us to solve for

y

(Coating Delta's low-intensity output), but provides no information about

x

. Therefore, Statement (1) alone is sufficient, while Statement (2) alone is not.

Step-by-Step Solution

Rephrase the question stem target

The average power output of Coating Gamma is

\frac{75 + 170 + x}{3} = \frac{245 + x}{3}

. To find this average, we only need to determine the value of

x

Simplifying the question target clarifies that finding

x

is both necessary and sufficient.

Evaluate Statement (1)

Statement (1) states that under High Intensity, Coating Gamma (

x

) is 10% greater than Coating Alpha (280). Thus,

x = 280 \times 1.10 = 308 \text{ W/m}^2

. We can compute the average as

\frac{245 + 308}{3} = 184.33 \text{ W/m}^2

Since a single unique numerical value for

x

is found, Statement (1) ALONE is sufficient.

Evaluate Statement (2)

Statement (2) gives the mean of Coating Delta as equal to the mean of Coating Beta. Mean of Coating Beta =

\frac{90 + 195 + 310}{3} = \frac{595}{3}

. Setting

\frac{y + 200 + 320}{3} = \frac{595}{3}

yields

y = 75 \text{ W/m}^2

Finding

y

gives information about Coating Delta, but provides no information regarding

x

for Coating Gamma. Thus, Statement (2) ALONE is not sufficient.

Key Concept

Target Rephrasing and Independent Statement Evaluation in Tabular Data Sufficiency

Estimated Time:2m 0s

Question

Answer

Step-by-Step Solution

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