Q. Let $S$ be the set of all five digit positive integers formed from the digits in the set ${1, 2, 3, 4, 5, 6, 7, 8, 9}$ without repetition. Find the number of these integers in which the digits $3, 5, 7$ appear in order (not necessarily consecutively) from left to right.

247 99 Permutations and Combinations Report Error

Answer: 0300

Q. Let S be the set of all five digit positive integers formed from the digits in the set {1,2,3,4,5,6,7,8,9} without repetition. Find the number of these integers in which the digits 3,5,7 appear in order (not necessarily consecutively) from left to right.