question of permutation and combination :-1)if the later letter word ;daughter;are to be arranged so that vowels occupy the odd places,then number of different word are ?(who it will be caculated
2)the sum of a;; 4 digit number containing the digit 2,4,6,8without repetitions?3)the number of 4 digit number greater than 5000 can be formed out of the digit 3,4,,5,6and 7(no digit is repeated).the number of such is