Question

Out of $25$ numbers, the mean of $15$ numbers is $36$ and the mean of the remaining number is $26$; find the mean of all the $25$ numbers.

Answer 1

No of observations is $25$

Mean of $15$ observations is $36$

Sum of observations is $36\times 15=540$

Mean of $10$ observations is $26$

Sum of observations is $26\times 10=260$

Total sum is $540+260=800$

Mean of the dta is $\frac{800}{25}=32$