The digit at units place of the sum ( 1 ! ) 2 + ( 2 ! ) 2 + ( 3 ! ) 2 + … .. + ( 2009 ! ) 2

( 5 ! ) 2 , ( 6 ! ) 2 , ( 7 ! ) 2 And so on will contain 0 in units place ∴ 1 + 4 + 36 + 576 ⇒ Units place is 7

Mathematics - Permutation & Combination Question with Solution | TestHub

MathematicsPermutation & CombinationMiscellaneous/MixedEasy2 minQB

MathematicsEasysingle choice

The digit at units place of the sum $(1!)^{2} + (2!)^{2} + (3!)^{2} + \dots .. + (2009!)^{2}$

Answer:

Solution:

$(5!)^{2}, (6!)^{2}, (7!)^{2}$ And so on will contain 0 in units place

$∴ 1 + 4 + 36 + 576 \Rightarrow$ Units place is 7

Stream:JEESubject:MathematicsTopic:Permutation & CombinationSubtopic:Miscellaneous/Mixed

⏱ 2mℹ️ Source: QB

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