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The-number-1000-has-certain-number-of-0s-at-the-end-what-the-the-first-non-zero-digit-1000-d-1-d-2-d-3-D00000-where-d-1-d-2-d-3-D-are-digits-Find-the-value-of-digit-D-




Question Number 482 by prakash jain last updated on 12/Jan/15
The number 1000! has certain number  of 0s at the end, what the the first non−zero  digit.  1000!=...d_1 d_2 d_3 D00000...  where d_1 ,d_2 ,d_3 ,D are digits.  Find the value of digit D.
Thenumber1000!hascertainnumberof0sattheend,whatthethefirstnonzerodigit.1000!=d1d2d3D00000whered1,d2,d3,Daredigits.FindthevalueofdigitD.
Commented by 123456 last updated on 12/Jan/15
1000!  2×5=10  1000!≡0(mod 2^p )→max p  1000!≡0(mod 5^q )→max q  1000!≡0(mod 10^s )→max s≡min(max p,max q)
1000!2×5=101000!0(mod2p)maxp1000!0(mod5q)maxq1000!0(mod10s)maxsmin(maxp,maxq)

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