JEE Main 2025 Mathematics question
Let P be the set of seven digit numbers with sum of their digits equal to 11. If the numbers in P are formed by using the digits 1,2 and 3 only, then the number of elements in the set P is :
Answer: (4)
Solution
Cases: 1111133 (21 ways), 1111223 (105 ways), 1112222 (35 ways). Total = 161.