Problem Solving

kalpanas wrote:Example: If a, b and c are integers and a.b + c is odd, what is true?
I. a + c is odd
II. b + c is odd
III. a.b.c is even
The answer provided for this is III.is this right?

ab + c = odd implies

Case 1: ab = even, c = odd
If a = even, b = even, then a + c = even + odd = odd, b + c = even + odd = odd, abc = even
If a = odd, b = even, then a + c = odd + odd = even, b + c = even + odd = odd, abc = even
If a = even, b = odd, then a + c = even + odd = odd, b + c = odd + odd = even, abc = even

Case 2: ab = odd, c = even
If a = odd, b = odd, then a + c = odd + odd = even, b + c = odd + even = odd, abc = even

It can be seen that abc = even in all the cases.

The correct answer is III.

pappueshwar wrote:hi anurag,


wats the final answer ? is it III ?

THE ANSWERS are getting covered by a dark spot, its very confusing in most of your solutions since i am solving the problem with out seeing your solution and checking if i am right or not.

request to remove the same so as to clear the ambiguity while posting the answer. is this dark spot a some system generated one ?

thanks
eshwar

Hi Eshwar!
Yes the correct answer is III. The black spot is the spoiler, and it's always better to hide the answer by using spoiler in my view.
Thanks,