Question

1) A set of 20 values have mean 54. Another set of values have mean 60. If the combined mean is 56, how many values are there in the latter set?​

Answer 1

Heya mate ...!

Here is your answer...

given , set of 20 values i.e., no.of observations=20

and let , total sum of observations be ' x ' .

by the problem , mean of 20 observations is 54

i.e., x/20 = 54

x = 54*20

x = 1080 ......................( 1 )

another set has the mean as 60 .

now , let no.of observations be ' y ' and total sum of observations be ' x ' .

i.e., x/y = 60

from ( 1 ) , 1080/y = 60

y = 18 ..................( 2 )

therefore , x = 1080 , y = 18

Therefore , the no.of values in the later set are 18 .

Hope it helps.....!