UPSC Prelims 2009·GS1·economy·basic concepts

A person has 4 coins each of different denomination. What is the number of different sums of money the person can form (using one or more coins at a time)?

Dalvoy logo
Reviewed by Dalvoy
UPSC Civil Services preparation
Last updated 23 May 2026, 3:31 pm IST
  1. A16
  2. B15Correct
  3. C12
  4. D11

Explanation

To solve this, consider each of the 4 coins. For every individual coin, there are two possibilities: either the person includes it in the sum or they do not include it. Since there are 4 coins and each has 2 possibilities, the total number of combinations is 2 multiplied by itself 4 times, which equals 16. However, these 16 combinations include the single case where none of the coins are selected, resulting in a sum of zero. The question asks for sums formed using one or more coins. Therefore, we must subtract that one empty case. Calculation: 16 minus 1 equals 15. Thus, the person can form 15 different sums of money. The correct answer is B.
economy: A person has 4 coins each of different denomination. What is the number of different sums of money the person can form (

Related questions

More UPSC Prelims practice from the same subject and topic.