Sum of 4 A.M between 18 and 3 is:

The correct answer is 42 because the sum of n arithmetic means between two numbers is always equal to n times their single arithmetic mean.

• Step 1 (Find the single A.M.): Calculate the single arithmetic mean between 18 and 3 using the average formula: (18 + 3) / 2 = 21 / 2 = 10.5.
• Step 2 (Calculate the sum): Use the property that the sum of n arithmetic means is n × A.M.. For 4 means, this results in 4 × 10.5 = 42.
• Incorrect Options:
  • 15 is incorrect because it is simply the absolute difference between 18 and 3, not the sum of the means.
  • 12 is incorrect because it does not satisfy the property of the sequence's arithmetic progression.
  • None of these is incorrect because option 3 matches the correct mathematical solution.