1) \(15x+24y=1755\)

2) \(x < 40\)

The OA is A

**Source: Veritas Prep**

00:00

**A**

**B**

**C**

**D**

**E**

In a certain first grade classroom, the average height is \(x\) inches for the \(5\) girls and \(y\) inches for the \(8\) boys. What is the average height for the \(13\) students in the classroom combined?

1) \(15x+24y=1755\)

2) \(x < 40\)

The OA is A

**Source: Veritas Prep**

1) \(15x+24y=1755\)

2) \(x < 40\)

The OA is A

- [email protected]
- GMAT Instructor
**Posts:**15628**Joined:**08 Dec 2008**Location:**Vancouver, BC**Thanked**: 5254 times**Followed by:**1266 members**GMAT Score:**770

00:00

**A**

**B**

**C**

**D**

**E**

swerve wrote: ↑Wed Jun 02, 2021 3:47 pmIn a certain first grade classroom, the average height is \(x\) inches for the \(5\) girls and \(y\) inches for the \(8\) boys. What is the average height for the \(13\) students in the classroom combined?

1) \(15x+24y=1755\)

2) \(x < 40\)

The OA is A

Source: Veritas Prep

This is a good candidate for rephrasing the target question.

We can think of this is a weighted averages question. So, we'll apply the following formula:

So, Average weight of classroom = (5/13)(x) + (8/13)(y)

= 5x/13 + 8y/13

= (5x + 8y)/13

So, we can REPHRASE the target question...

Notice that we have (5x + 8y) "hiding" in the above equation.

Take 15x + 24y = 1755 and factor the left side to get: 3(5x + 8y) = 1755

Divide both sides by 3 to get: 5x + 8y = 585

So, (5x + 8y)/13 = (585)/13 =

Since we can answer the REPHRASED target question with certainty, statement 1 is SUFFICIENT

No information about y, which means there's no way to determine the value of (5x + 8y)/13

Since we cannot answer the REPHRASED target question with certainty, statement 2 is NOT SUFFICIENT

Answer: A