IIT JEE , AIEEE Forum - Mathematics , Algebra

sangeetha5491

find the number of ways in which one or more letters be selected from the letters XXXX YY ZZZ ABCD.

rathin_123

can we repeat one letter?

if we can then it will be

13! / 4!2!3! =21621600

sangeetha5491

i tried the same thing but the answer given along with the question is 959

chemicaltester

now let xxxx represent a group say X
also let YY represent another group =Y
same for Z
now the no of groups are
X ,Y ,Z ,A ,B ,C ,D

now one letter can be selected in 13 ways
two letters can be selected by 7p1 *6p1 *4c2*2c2* 3c2
similarly three letter can be selected 7p1*6p1* 5p1 *4c3 *1 *3c3

continuing in that way u will get 7 cases
summating them u may get the answer
not sure it will give or not

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