Question

The mean of 10 numbers is 15 and that of another 20 number is 24 then the mean of all 30 observations is_.​

Answer 1

Answer:

21

Step-by-step explanation:

sum of 10 numbers= 10×15= 150

sum of 20 numbers= 20×24= 480

sum of 30 numbers= 150 +480= 630

Since mean = Sum of all observations/Total number of observations,

mean of all 30 observations = 630÷30= 21

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