JEE PYQ: Permutation And Combination Question 4
Question 4 - 2021 (18 Mar Shift 1)
The sum of all the 4-digit distinct numbers that can be formed with the digits 1, 2, 2 and 3 is:
(1) 26664
(2) 122664
(3) 122234
(4) 22264
Show Answer
Answer: (1)
Solution
Total distinct numbers $= \frac{4!}{2!} = 12$. When 1 is at unit place: 3 numbers, when 2: 6 numbers, when 3: 3 numbers. Sum $= (3 + 12 + 9)(10^3 + 10^2 + 10 + 1) = 24 \times 1111 = 26664$.
BETA
