Show that one of three consecutive odd integers is a multiple of 3
Answers
Answered by
7
Since it is an odd number
So
1st number be 2n+1
Being consecutive odd
2nd number will be 2n+1+2=2n+3
And
3rd number 2n+5
2n is always an even number and condition will revolve around this only giving rise to 2 cases.
Case 1 : if 2n is divisible by 3
then 2n + 3 will always be divisible by 3.
Case 2 : if 2n is not divisible by 3
Then remainder is either 1 or 2
Case 2 (a). Remainder 1 implies 2n-1 is divisible by 3.
If multiple of 3 is added to 2n-1 that will also be divisible by 3
2n-1 +3 + 3
=2n-1 +2×3
=2n+5
So 2n+5 is divisible by 3
Case 2 (b) Remainder 2 implies 2n-2 is divisible by 3.
If multiple of 3 is added to 2n-2 that will also be divisible by 3
2n-2 +3
=2n-2 +1×3
=2n+1
So 2n+1 is divisible by 3
So from all the above case it os verified that out of 3 consecutive odd number one will always be divisible by 3.
So
1st number be 2n+1
Being consecutive odd
2nd number will be 2n+1+2=2n+3
And
3rd number 2n+5
2n is always an even number and condition will revolve around this only giving rise to 2 cases.
Case 1 : if 2n is divisible by 3
then 2n + 3 will always be divisible by 3.
Case 2 : if 2n is not divisible by 3
Then remainder is either 1 or 2
Case 2 (a). Remainder 1 implies 2n-1 is divisible by 3.
If multiple of 3 is added to 2n-1 that will also be divisible by 3
2n-1 +3 + 3
=2n-1 +2×3
=2n+5
So 2n+5 is divisible by 3
Case 2 (b) Remainder 2 implies 2n-2 is divisible by 3.
If multiple of 3 is added to 2n-2 that will also be divisible by 3
2n-2 +3
=2n-2 +1×3
=2n+1
So 2n+1 is divisible by 3
So from all the above case it os verified that out of 3 consecutive odd number one will always be divisible by 3.
Answered by
9
Step-by-step explanation:
Let 3 consecutive positive integers be n, n + 1 and n + 2 .
Whenever a number is divided by 3, the remainder we get is either 0, or 1, or 2.
:
Therefore:
n = 3p or 3p+1 or 3p+2, where p is some integer
If n = 3p = 3(p) , then n is divisible by 3
If n = 3p + 1, then n + 2 = 3p +1 + 2 = 3 p + 3 = 3 ( p + 1 ) is divisible by 3
If n = 3p + 2, then n + 1 = 3p + 2 + 1 = 3p + 3 = 3(p + 1) is divisible by 3
Thus, we can state that one of the numbers among n, n+1 and n+2 is always divisible by 3
Hence it is solved.
THANKS
#BeBrainly.
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