JEE MAIN - Mathematics (2020 - 9th January Morning Slot - No. 6)
If the number of five digit numbers with distinct
digits and 2 at the 10th place is 336 k, then k
is equal to :
6
8
4
7
Explanation
_9th_January_Morning_Slot_en_6_1.png)
Except 1 and 2 there are eight options on first place and only one option at fourth place possible which is digit '2'.
Remaining three places can be filled by any three digits out of 1, 3, 4, 5, 6, 7, 8 and 9.
$$ \therefore $$ No. of five digits numbers = 8 $$ \times $$ 8 $$ \times $$ 7 $$ \times $$ 1 $$ \times $$ 6 = 336 $$ \times $$ 8
Also 336k = 336 $$ \times $$ 8
$$ \Rightarrow $$ k = 8
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