Advertisements
Advertisements
प्रश्न
In a class test in mathematics, 10 students scored 75 marks, 12 students scored 60 marks, 8 students scored 40 marks and 3 students scored 30 marks. Find the mean of their score
Advertisements
उत्तर
Total marks of 10 students = 10 × 75 = 750
Total marks of 12 students = 12 × 60 = 720
Total marks of 8 students = 8 × 40 = 320
Total marks of 3 students = 3 × 30 = 90
Total marks of (10 + 12 + 8 + 3) 33 students
= 750 + 720 + 320 + 90
= 1880
Mean of marks = `1880/33`
= 56.97 or 57 approximately
Aliter:
Total number of students = 10 + 12 + 8 + 3
= 33
Mean of their marks
= `"Total marks"/"Number of students"`
= `(10 xx 75 + 12 xx 60 + 8 xx 40 + 3 xx 30)/33`
= `(750 + 720 + 320 + 90)/33`
= `1880/33`
= 56.97 or 57 approximately
APPEARS IN
संबंधित प्रश्न
Mean of 100 observations is 40. The 9th observation is 30. If this is replaced by 70 keeping all other observations same, find the new mean.
The following table shows the electricity (in units) used by 25 families of Eklara village in a month of May. Complete the table and answer the following questions.
| Electricity used (units) `bb(x_i)` |
No. of Families (frequency) `bb(f_i)` |
`bb(f_ix_i)` |
| 30 | 7 | _________ |
| 45 | 2 | __________ |
| 60 | 8 | __________ |
| 75 | 5 | __________ |
| 90 | 3 | __________ |
| N = _________ | `sum f_ix_i` = ______ |
- How many families use 45 units electricity?
- State the score, the frequency of which is 5.
- Find N, and `sum f_ix_i`
- Find the mean of electricity used by each family in the month of May.
A batsman scored the following number of runs in six innings: 36, 35, 50, 46, 60, 55. Calculate the mean runs scored by him in an inning.
The mean of a set of seven numbers is 81. If one of the numbers is discarded, the mean of the remaining numbers is 78. The value of discarded number is
The algebraic sum of the deviations of a set of n values from their mean is
The mean of first ten natural numbers is ____________
The mean of first fifteen even numbers is ____________
Arithmetic mean of 15 observations was calculated as 85. In doing so an observation was wrongly taken as 73 for 28. What would be correct mean?
Find the mean of first 10 prime numbers and first 10 composite numbers
The following are weights (in kg) of 12 people.
70, 62, 54, 57, 62, 84, 75, 59, 62, 65, 78, 60.
- Find the mean of the weights of the people.
- How many people weigh above the mean weight?
- Find the range of the given data.
