4 votes 4 votes Consider the set of $4$-digit positive integers. How many of them are odd and have distinct digits? Combinatory goclasses2024-dm-4-weekly-quiz numerical-answers goclasses combinatory 1-mark + – GO Classes asked May 3, 2022 edited May 16, 2023 by Lakshman Bhaiya GO Classes 287 views answer comment Share Follow See all 0 reply Please log in or register to add a comment.
6 votes 6 votes There are $5 \cdot 8 \cdot 8 \cdot 7 = 2, 240.$ The recipe is as follows: Choose the last digit (which must be odd) – $5$ choices Choose the first digit (can’t be zero and must be different from the last) – $8$ choices Choose the second digit (can’t be the same as either the first or last)– $8$ choices Choose the third digit (can’t be the same as either the first, second, or last) – $7$ choices GO Classes answered May 3, 2022 edited May 3, 2022 by Lakshman Bhaiya GO Classes comment Share Follow See all 0 reply Please log in or register to add a comment.