**(1) Which class has the maximum number of students?**

**Solution:**

Class 60-70 has maximum number of students

**(2) Write the classes having zero frequency.**

**Solution:**

Class 20-30 and class 90-100 have zero frequency

**(3) What is the class-mark of the class, having frequency of 50 students?**

**Solution:**

Frequency 50 students is for class 50-60

Class mark for this class is 55

**(4) Write the lower and upper-class limits of the class whose class mark is 85.**

**Solution:**

Class mark is 85 for class 80-90

Lower limit = 80

Upper limit = 90

**(5) How many students are in the class 80-90?**

**Solution:**

There are 15 students in class 80-90