Question

If the mean of first 10 observations is 15 and the mean of 15 observations is 10.

Find the mean of all observations.​

Answer 1

$\huge{\fbox{\fbox{\orange{\mathfrak{Answer\::}}}}}$150

$\huge{\fbox{\red{\mathfrak{Given:}}}}$

• Let observation consider as O

➡️10 O =15

➡️15 O=10

So,

➡️10×15=150

➡️15×10=150

➡️

$\frac{150 + 150}{2}$

$\frac{300}{2}$

$150$

So, mean =150