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1 vote

Is x + y – z + t even?

I. x + y + t is even.

II. tz is odd.

- if the questions can be answered with the help of both the statements but not with the help of either statement itself.
- if the question can not be answered even with the help of both the statements.
- if the question can be answered with the help 0 statement II alone
- if the question can be answered with the help of statement I alone

0 votes

To find if x + y – z + t is even or not, we need to know each of x, y, z, t is even or odd.

It is given that x + y + t is even .... from I

We now just need to check if z is even or odd.

If z is even, then (even - even) will be even. If z is odd, then (even - odd) will be odd.

From II, we can conclude that both t and z are odd as product of two odd numbers is odd.

even - odd = odd

So, we need both the statements to conclude if x + y - z + t is even.

A is the answer.

It is given that x + y + t is even .... from I

We now just need to check if z is even or odd.

If z is even, then (even - even) will be even. If z is odd, then (even - odd) will be odd.

From II, we can conclude that both t and z are odd as product of two odd numbers is odd.

even - odd = odd

So, we need both the statements to conclude if x + y - z + t is even.

A is the answer.