Multiple choice

If mean of $7$ observation is $10$ & mean of set of $ 3 $ observation is $5$ , then mean of combined set is $8.5$.

  1. Both Assertion &. Reason are individually true & Reason is correct explanation of Assertion.

  2. Both Assertion & Reason are individually true but Reason is not the correct (proper) explanation of Assertion.

  3. Assertion is true Reason is false.

  4. Assertion is false Reason is true.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Assertion: Combined mean = (7*10 + 3*5) / (7+3) = (70 + 15) / 10 = 85 / 10 = 8.5. The assertion is true. The reason is the formula for combined mean, which is the correct explanation.

AI explanation

The combined mean formula is the sum of all observations divided by the total number of observations. The total sum is (7 times 10) + (3 times 5) = 85, and the total number of observations is 7 + 3 = 10. Dividing 85 by 10 gives the combined mean of 8.5, confirming the assertion, and the mathematical calculation serves as the correct explanation for it.

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