If a, b, c are consequitive positive integers and a<b<c, which of the following must be true?

1. c-a=2

2. abc is an even integer

3. (a+b+c) /3 is an integer

1.

a=a

b=a+1

c=a+2

c-a=a+2-a=2.

Correct

2. abc

a can be either even or odd

if a=even; abc=even;

if a=odd,b=even; abc=even

Rule:

multiple of any number of integers if atleast once multiplied by an even number will result in even.

even*even=even

even*odd=even

Correct

3. (a+b+c) /3 is an integer

Again;

a=a

b=a+1

c=a+2

a+b+c=(a+a+1+a+2)=3a+3

3a is always divisible by 3

3 is divisible by 3.

Thus "3a+3" is also divisible by 3.

Rule:

if integer x is divisible by n

and

integer y is divisible by n

then; x+y must be divisible by n

Correct.

Ans : "E"

_________________

~fluke

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