The problem is to find the percentage of students who had marks ranging from 35 to 50, based on the given bar chart.

1. Problem Description

The problem is to find the percentage of students who had marks ranging from 35 to 50, based on the given bar chart.

2. Solution Steps

First, we need to read the frequency of students in each mark range from the bar chart.

- Marks around 20: Frequency = 20

- Marks around 35: Frequency = 35

- Marks around 40: Frequency = 40

- Marks around 50: Frequency = 45

- Marks around 65: Frequency = 25

- Marks around 80: Frequency = 15

Next, calculate the total number of students.

Total number of students = 20 + 35 + 40 + 45 + 25 + 15 = 180

Now, calculate the number of students with marks ranging from 35 to

5

0. This includes the students with marks around 35, 40, and

5

0. Number of students with marks from 35 to 50 = 35 + 40 + 45 = 120

Calculate the percentage of students with marks ranging from 35 to

5

0. Percentage = (Number of students with marks from 35 to 50 / Total number of students) * 100

Percentage = (120 / 180) * 100

Simplify the fraction: 120/180 = 12/18 = 2/3

Percentage = (2/3) * 100

Percentage = 200/3

Percentage = 66.666...%

Percentage = $66\frac{2}{3}\%$

3. Final Answer

D. $66\frac{2}{3}\%$