# Chapter 12 | Data Handling | Class-7 DAV Secondary Mathematics

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## Chapter 12 Worksheet 1 | Data Handling | Class-7 DAV Secondary Maths

1. The attendance in a school for a week is as follows:

425, 430, 400, 408, 410, 423

Calculate the mean of the attendance.

2. The heights of ten boys were measured In centimetres and the results were as follows:

143. 132. 149. 148. 151, 146, 135, 128, 139. 150

(i) What is the height of the tallest boy?

(ii) What is the height of the shortest boy?

(iii) What is the range of the data?

(iv) Find the mean height.

(v) How many boys are there whose heights are less than the mean height?

3. A group of students was given a special test. The test was completed by various students in the following duration of time (in minutes):

17, 19, 20, 22, 24, 24, 28, 30, 30, 36

(i) Find the mean time taken by the students to complete the test.

(ii) Find the new mean, if another student who took 14 minutes is also included.

4. The enrolment of a school during seven consecutive years was as follows:

1580, 2020, 2580, 3200, 3550, 3710, 4010

(i) Find the mean enrolment of the school for this period.

(ii) Find the new mean, if the enrolment of the current year, that is, 4,270 is also included.

5. in a factory the total number of workers are 25. Out of them, the average monthly salary of 15 workers is Rs.8,500 whereas the other 10 workers have an average salary of Rs. 9,800. Find the monthly average salary of all the 25 workers.

6. The average salary of 19 workers in a factory is Rs 12,000 per month. If the salary of the manager is Rs. 42,000 per month, find the average monthly salary paid to all the employees.

7. The mean of nine observations was found to be 35. Later on, it was discovered that an observation 81 was misread as 18. Find the correct mean of the observations.

8. The mean of five numbers is 27. If one number is excluded, their mean is 25. Find the excluded observation,

9. The mean of eight numbers is 27. If one more number is included, then the mean is 26. Find the included number.

10. In a certain hospital, the mean birth rate of a week was 35. If the mean birth rate from Monday to Thursday was 32 and that of Thursday to Sunday was 36, find the number of births on Thursday.

## 4 thoughts on “Chapter 12 | Data Handling | Class-7 DAV Secondary Mathematics”

1. Question number 6 me 19 workers h..tho 20 se divided kyun kiya