mkrishnabdrr wrote:
If P is an odd integer and (P^2 + Q * R) is an even integer, then which of the following must be true?
A. either Q or R is an odd integer
B. either Q or R is an even integer
C. both Q and R are odd integer
D. both Q and R are even integers
E. nothing can be concluded
P is an odd integer
(P^2 + Q * R) is an even integer
P^2 is also an odd integer... So, for (P^2 + Q * R) to be an even integer, Q*R must be odd integer.
Now Q*R can be odd in two cases.
1st : Both are integers : In this case Q and R both are odd integers.
2nd : One of them is integer and other is fraction : In this case the first integer may be odd or even and second integer is a fraction.
So, Nothing can be concluded about Q & R in terms of being odd or even or integral form.
Answer EThis is a very tricky question. People, including me, get caught in the trap and mark the wrong answer as C. Be very careful while reading such questions... A simple mistake will cost your marks. Finally don't forget to appreciate.
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