Question

The average of 19 observation is 54. If the average of first 10 observations is 56 and that of
last 10 observations is 53. Find the tenth observation.
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Answer 1

Answer:

19*54= 1026

10*56= 560

10*53= 530

sum of 20 = 1090

to find the tenth 1090-1026=64

Answer 2

☞Question.

The average of 19 observation is 54. If the average of first 10 observations is 56 and that of

last 10 observations is 53. Find the tenth observation.

☞.Solution.

☞The average of 19 observations is $\sf\green{54}$

➝So sum of all the observations = $\sf\green{19×54 = 1026}$

☞avrage of first10 observations = $\sf\green{56}$

➝So total of first 10 observations= $\sf\green{10 × 56 = 560}$

☞Similarly the sum of the last 10 observations

➝$\sf\green{10×53 = 530}$

☞Total of the sum of the first ten and the last ten observations = $\sf\green{560+530 = 1090}$

➝In the above 10th observation is included two times (in the first ten as well as in the last ten)

➝So the 10 th observation =.$\sf\green{1090 - 1026= 64}$