total possible 4 digit numbers from given 6 digits

Question

total possible 4 digit numbers from 2,3,5,6,7,9  without repetition?  total numbers possible less than 500?

360, 130             360, 100               240, 120           none

Answer 1

4 Digit Numbers Possible = 6C4 * 4! =15*24=360
Numbers less than 500= Starting with 2,3 * 5C3 *3!

=2* 20 * 6

= 120

Comments

 2,3 * 5C3 *3!  -  Here why  5C3 ?

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First Digit = 2,3

Reamaining 3 digits can be choosen from 5 digits i.e 5C3 and they can be arranged in 3! ways

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Total possible 

6 choice at first place

5 choice  at second place 

4 choices  at third place 

3 choice  at last

Total  =6*5*4*3=360

For less than 5000

Two choice at first place 

Five choice at second 

Four at Third place

Three  at last place 

2*5*4*3=120

For less than 500, 

​No number possible with given digits, 0.

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Cant we do like

Without repitition:2*5*4

With rep. : 2*6*6?? For less than 500