Re: GRE Math Challenge #38-consecutive positive integers & a < b
[#permalink]
15 Jan 2018, 05:01
the addition or a product of two numbers can result in a odd number in the following 2 circumstances
even+odd= odd
odd+even= odd
odd*odd = odd
consecutive integers are in the format
odd,even,odd
even,odd,even
abc= (a*b)*c = ab must be even hence abc must be even
If a,b,c are in the form odd,even,odd for eg. 1,2,3 then a+b = odd and c will be odd therefore a+b+c will be even
If a,b,c are in the form even,odd,even eg. 2,3,4 then, bc=even and a+bc =even
If If a,b,c are in the form even,odd,even eg.2,3,4 then,a(b+c) = 2(3+4) = 14=even
(a+b)(b+c) follows (odd+even)(even+odd) or (even+odd)(odd+even) in both scenarios the final product will be odd*odd = odd
(E)