In Lee Middle School, the ratio of the number of fifth-graders to the number of sixth-graders is 5 to 4, and there are 16 more fifth-graders. If the ratio of the number of sixth-graders to the number of seventh-graders is 2 to 3, what is the mean number of students in the three grades? Your Answer:

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### Problem Statement:

**In Lee Middle School, the ratio of the number of fifth-graders to the number of sixth-graders is 5 to 4, and there are 16 more fifth-graders. If the ratio of the number of sixth-graders to the number of seventh-graders is 2 to 3, what is the mean number of students in the three grades?**

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**Your Answer:**

[Text Box for User Input] 

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### Explanation:

In this problem, we need to find the mean number of students in the fifth, sixth, and seventh grades given the following ratios and information:
1. The ratio of fifth-graders to sixth-graders is 5:4.
2. There are 16 more fifth-graders than sixth-graders.
3. The ratio of sixth-graders to seventh-graders is 2:3.

Here's how to solve this step-by-step:

1. **Set up the ratios using variables:**
   - Let the number of sixth-graders be \( 4x \).
   - Hence, the number of fifth-graders is \( 5x \) (since the ratio is 5:4).

2. **Account for the additional 16 fifth-graders:**
   \[
   5x = 4x + 16
   \]
   Solve for \( x \):
   \[
   x = 16
   \]

3. **Calculate the actual number of fifth and sixth graders:**
   - Sixth-graders: \( 4x = 4 \cdot 16 = 64 \)
   - Fifth-graders: \( 5x = 5 \cdot 16 = 80 \)

4. **Use the second ratio to find the number of seventh-graders:**
   - The ratio of sixth-graders to seventh-graders is 2:3.
   - If the number of sixth-graders is 64 (which is \( 2y \)), then the number of seventh-graders is \( 3y \).
   - Setting \( 2y = 64 \), we get \( y = 32 \).

   Number of seventh-graders:
   \[
   3y = 3 \cdot 32 = 96 
   \]

5. **Calculate the mean number of students:**
   - Total number of students: \( 80 + 64 + 96 =
Transcribed Image Text:### Problem Statement: **In Lee Middle School, the ratio of the number of fifth-graders to the number of sixth-graders is 5 to 4, and there are 16 more fifth-graders. If the ratio of the number of sixth-graders to the number of seventh-graders is 2 to 3, what is the mean number of students in the three grades?** --- **Your Answer:** [Text Box for User Input] --- ### Explanation: In this problem, we need to find the mean number of students in the fifth, sixth, and seventh grades given the following ratios and information: 1. The ratio of fifth-graders to sixth-graders is 5:4. 2. There are 16 more fifth-graders than sixth-graders. 3. The ratio of sixth-graders to seventh-graders is 2:3. Here's how to solve this step-by-step: 1. **Set up the ratios using variables:** - Let the number of sixth-graders be \( 4x \). - Hence, the number of fifth-graders is \( 5x \) (since the ratio is 5:4). 2. **Account for the additional 16 fifth-graders:** \[ 5x = 4x + 16 \] Solve for \( x \): \[ x = 16 \] 3. **Calculate the actual number of fifth and sixth graders:** - Sixth-graders: \( 4x = 4 \cdot 16 = 64 \) - Fifth-graders: \( 5x = 5 \cdot 16 = 80 \) 4. **Use the second ratio to find the number of seventh-graders:** - The ratio of sixth-graders to seventh-graders is 2:3. - If the number of sixth-graders is 64 (which is \( 2y \)), then the number of seventh-graders is \( 3y \). - Setting \( 2y = 64 \), we get \( y = 32 \). Number of seventh-graders: \[ 3y = 3 \cdot 32 = 96 \] 5. **Calculate the mean number of students:** - Total number of students: \( 80 + 64 + 96 =
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