Question 1204431
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Determine whether 280 is a term in the G.P 1,3,9,27…
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Good question !


The solution is very simple: each term of the GP is a degree of 3; 
so, in particular, starting from the second term, each term is a multiple of 3.


From the other side, the number 280 is NOT a multiple of 3 (just because 
the sum of its digits, 2+8+0 = 10 is not a multiple of 3).


So, the number 280 is not a member of the given G.P.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<U>ANSWER</U>.


Solved.