Question

. If the mean of 10 numbers is 7 and mean of 15 numbers is 12, then the combined mean is I
a) 7
b) 12
c) 10
d) 15​

Answer 1

Answer:

10

Step-by-step explanation:

Mean of 10 numbers = 7

Mean = sum of observations / total no.of observations

7 = x/10

x = 70

Mean of 15 numbers = 12

Mean = sum of observations / total no.of observations

12 = y/15

y = 180

Combined mean = 180+70/10+15

= 250/25

= 10

Answer 2

Sum of first 10 numbers is 10*7= 70( mean = sum of numbers/total numbers)
Now sum of 15 numbers =12*15
180
Combined mean = 70+180/25
250/25
= 10