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What is the last non zero digit of 96! ?
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- given :1*2*3*....96
first take 1st 10 digits
1*2*3*4*5*6*7*8*9*10
now ignore those which give a product of 10
thus take only 1*2*3*4*6*8*9
note that we havnt taken 2 and 5 as it gives a product of 10.similarly we ignored 10
now the product of 1 2 3 4 6 8 9 gives 8 in units place
every 10 digits set is taken and each set gives 8 digit i units place in the product of those 10 digits
now from 1 to 90 we have 8*8*....nine times
now for the above product we have 8 as units digit
Now find out the units digit for 91*92*93*94*95*96....again here we xclude 10
and we take non zero digit i.e 2
now 8*2 gives 6 in the units place
thus ans is 6
- 12 years agoHelpfull: Yes(20) No(3)
- Given the word “Parrot”. Find the 20th word in dictionary order. can any one tell me how to solve this
- 12 years agoHelpfull: Yes(8) No(2)
- If we try to compute 96!
then
4*z(96/5)*z(6)
=4*z(19)*8
96!,Z(n) = {4 if tens digit is odd and 6 if tens digit is even) *
Z(n/5) * z(Units digit).=8*(4*z(19/5)*z(9))
=8*(4*z(3)*8)
=8*(4*6*8)
=1536 i.e last digit is 6 - 12 years agoHelpfull: Yes(6) No(0)
- the answer will be 6...
its difficult to xplain as it involves long theory
- 12 years agoHelpfull: Yes(3) No(0)
- Z(n) denotes the last non zero digit in n!
Z(n) = 4 if tens digit is odd and 6 if tens digit is even
Z(n/5) * z(Units digit).
example
last digit of 96!
Z(96) = 6 * Z(96/5) * Z(6)
= 6 * z(19) * last non zero digit of 6!
= 6 * last non zero digit of 19! * last non zero digit of 6!
= 6 * by same process i got 2 * last non zero digit of (120)
= 6 * 2 * 2
= 24 (answer is the last digit ie 4)
= 4 - 12 years agoHelpfull: Yes(3) No(4)
- the ans is 6.
using formula 4*D(n/5)*D(unit place of 96)
4*D(19)*D(6)
4*[4*D(3)*D(9)]*D(6)
4*4*6*8*2
=1536
ans = 6
- 12 years agoHelpfull: Yes(3) No(2)
- 96! has numbers that are multiple of 5 and the rest.. rest of the numbers have 6 as their last digit only. numbers from 91 to 94 have 4.. so 6*4 =4 is the last digit for that group. now for 5 multiples write 5=5*1, 10=5*2 and so on till 95.. shift the 1 , 2,... 19 to the second group. giving 6 there too.. now what should be multiplied with 4 to give 4 as a last digit. either 1 or 6.. that is the answer.
- 12 years agoHelpfull: Yes(2) No(0)
- ans is 6.
- 12 years agoHelpfull: Yes(1) No(0)
- miss farhana forget 7 in his process...including 7 n then by repeating same procedure....i think answer will be 2
- 12 years agoHelpfull: Yes(1) No(2)
- kavita plz give the solution more clear...
i cant understand this one
- 12 years agoHelpfull: Yes(0) No(0)
- ans is 2bcoz product of 91 92 93 94 96 gives unit digit 4 for remain semeas farhan 8*4=2
- 12 years agoHelpfull: Yes(0) No(0)
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