How many odd 4-digit numbers, all of the digits different, maybe formed from the digits 0-9 inclusive, if there must be a 5 inthe number? a)Solve using indirect ( back-door) approach. b)Give an alternate solution to this problem which uses thedirect approach. How many odd 4-digit numbers, all of the digits different, maybe formed from the digits 0-9 inclusive, if there must be a 5 inthe number? a)Solve using indirect ( back-door) approach. b)Give an alternate solution to this problem which uses thedirect approach.