How many numbers greater than 24000 can be formed by using the digits 1, 2, 3, 4, 5 when no digit is repeated, is

Required number of numbers

= Total number of numbers formed by the digits 1, 2, 3, 4, 5

- Number of numbers having 1 at ten thousand's place

- Number of numbers having 2 at ten thousand's place and 1 at thousand's place

- Number of numbers having 2 at ten thousand's place and 3 at thousand's place

$= 5! -4! -3! -3! =120-24-6-6=84$.