The average of 11 numbers is 36. The average of 9 of them is 34. If the remaining two numbers are in the ratio 2 : 3, find the smaller number.

Difficulty: Medium

Correct Answer: 36

Explanation:

Introduction / Context:Given averages for the whole and a subset, we can compute the total of the remaining items. With a ratio for those two items, convert the total to parts and extract each number.

Given Data / Assumptions:

  • 11-number mean = 36 ⇒ total T = 396.
  • 9-number mean = 34 ⇒ subtotal S = 306.
  • Remaining two are in ratio 2 : 3.

Concept / Approach:Sum of the remaining two = T − S. If they are 2k and 3k, then 5k equals that sum; solve k to get both, then choose the smaller (2k).

Step-by-Step Solution:

Sum of two = 396 − 306 = 90 Let numbers be 2k and 3k ⇒ 5k = 90 ⇒ k = 18 Smaller number = 2k = 36

Verification / Alternative check:Other number = 54; together 36 + 54 = 90. Totals reassemble correctly: 306 + 90 = 396 ⇒ average 36.

Why Other Options Are Wrong:18, 54, 48: Do not match the ratio and total simultaneously. 36 is the unique smaller value.

Common Pitfalls:Dividing 90 by 2 (getting 45, 45) and ignoring the 2 : 3 ratio, or picking the larger number by mistake.

Final Answer:36

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