Question 31

Mathematics Permutation and Combination Easy

Given below are two statements:
Statement I: The number of different numbers each of 6 digits that can be formed by using all the digits \( 1,2,1,0,2,2 \) is 50 .
Statement II: These are 4536 possibilities of writing the fourdigit numbers which have all distinct digits.
In the light of the above statements, choose the correctanswer from the options given below

(A) Both Statement I and Statement II are true
(B) Both Statement 1 and Statement II are false
(C) Statement I is true but Statement II is false
(D) Statement I is false but Statement II is true
View Dynamic Solution & Explanation
Correct Solution: Option A

Step-by-step Solution:

Statement I: The number of different numbers each of 6 digits that can be formed by using all the digits 1, 2, 1, 0, 2, 2 is 50. We need to calculate the number of distinct 6-digit numbers that can be formed using the digits 1, 2, 1, 0, 2, 2. Note that 0 cannot be the first digit in a 6-digit number. 1. Total digits: 6 (with repetitions: two 1's and three 2's, and one 0). 2. Total permutations without restrictions: \[ \frac{6!}{2! \times 3!} = \frac{720}{2 \times 6} = 60 \] 3. Subtract the permutations where 0 is the first digit: - Fix 0 as the first digit. - Remaining digits: 1, 2, 1, 2, 2. - Permutations of the remaining digits: \[ \frac{5!}{2! \times 3!} = \frac{120}{2 \times 6} = 10 \] 4. Valid 6-digit numbers: \[ 60 - 10 = 50 \] \[Statement I is true.\] Statement II: There are 4536 possibilities of writing the four-digit numbers which have all distinct digits. We need to calculate the number of 4-digit numbers with all distinct digits. 1. First digit (thousands place): Cannot be 0, so there are 9 possible choices (1-9). 2. Second digit (hundreds place): Can be 0, but must be distinct from the first digit, so 9 choices. 3. Third digit (tens place): Must be distinct from the first two digits, so 8 choices. 4. Fourth digit (units place): Must be distinct from the first three digits, so 7 choices. Total number of 4-digit numbers with all distinct digits: \[ 9 \times 9 \times 8 \times 7 = 4536 \] Statement II is true. Conclusion: - Statement I is true. - Statement II is true. Therefore, the correct answer is: A. Both Statement I and Statement II are true