Equal count of three note types: A man has ₹480 in ₹1, ₹5, and ₹10 notes. The count of notes of each denomination is equal. What is the total number of notes he has?

Difficulty: Easy

Correct Answer: 90

Explanation:


Introduction / Context:
This is a neat arithmetic application of equal counts across denominations. The total value is a simple multiple of the sum of the denominations, scaled by the common count. We then multiply by three to get the total number of notes.


Given Data / Assumptions:

  • Total money = ₹480.
  • Denominations: ₹1, ₹5, ₹10.
  • Let n be the equal count for each denomination.


Concept / Approach:
Total value = n*(1 + 5 + 10) = 16n. Solve 16n = 480, then compute total notes = 3n. This linear setup avoids any need for trial and error.


Step-by-Step Solution:

16n = 480 ⇒ n = 480/16 = 30Total number of notes = 3n = 90


Verification / Alternative check:
Compute value by denomination: 30*₹1 + 30*₹5 + 30*₹10 = ₹30 + ₹150 + ₹300 = ₹480, exactly the given total.


Why Other Options Are Wrong:

  • 45, 60, 75, 120: Do not correspond to 3n with n an integer satisfying 16n = 480.


Common Pitfalls:
Confusing equal value with equal count, or summing denominations incorrectly (1 + 5 + 10 = 16, not 15).


Final Answer:
90

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