Mathematics
The combined mean of three groups is 12 and the combined mean of first two groups is 3. If the first, second and third groups have 2, 3 and 5 items respectively, then the mean of third group is :
10
12
13
21
Related Questions
In a class of 100 students, the mean marks obtained in a certain test is 30 and in another class of 50 students the mean marks obtained in the same test is 60. The mean marks obtained by the students of both the classes taken together is :
40
45
48
50
A distribution consists of three components with frequencies 45, 40 and 15 having their means 2, 2.5 and 2 respectively. The mean of the combined distribution is :
2.1
2.2
2.3
2.4
The mean weight of 17 boxes is 92 kg. If 18 new boxes are added, the mean weight increases by 3 kg. What will be the mean weight of the 18 new boxes?
91.8 kg
92.8 kg
97.8 kg
98.8 kg
Consider the following distribution :
Class Frequency 0 – 20 17 20 – 40 28 40 – 60 32 60 – 80 f 80 – 100 19 If the mean of the above distribution is 50, what is the value of f ?
24
34
56
96