Question

Which of the following number is exactly divisible by 3? 1

a) 5470

b) 5211

c) 4514

d) 7901​

Answer 1

Answer:

b ) 5211 this is divisible by 3

Answer 2

$\underline{ \pink{ Divisibility \: rule \:by \: 3 :}}$

If sum of the digits is multiple of 3 then the number is divisible by 3.

$a ) 5470\\Sum \:of \:the \:digits \\= 5+4+7+0 \\= 16 \: ( not \: multiple \: of \: 3 )$

$\red{ \therefore 5470 \: is \: not \: divisible \: by \: 3 }$

$b ) 5211\\Sum \:of \:the \:digits \\= 5+2+1+1 \\= 9 \: ( multiple \: of \: 3 )$

$\green{ \therefore 5211 \: is \: divisible \: by \: 3 }$

$c ) 4514\\Sum \:of \:the \:digits \\= 4+5+1+4 \\= 14 \: ( not \: multiple \: of \: 3 )$

$\red{ \therefore 4514 \: is \: not \: divisible \: by \: 3 }$

$d ) 7901\\Sum \:of \:the \:digits \\= 7+9+0+1 \\= 17 \: ( not \: multiple \: of \: 3 )$

$\red{ \therefore 7901 \: is \: not \: divisible \: by \: 3 }$

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