Question

17. Is x + y - Z + t even ?
I.
x + y + t is even.
II. t and z are odd.​

Answer 1

Answer:

Use the rules that

(a) product of two odd or even numbers are odd and even respectively.

(b) the quotient of the odd number ÷ even number or vice-versa may or may not be strictly odd or even.

a. ab must be a even number and

c

ab

may be even number or a fraction or odd number and xy must be a odd number

therefore it can be justified in some case.

b.

x

ab

is always a fraction or even number and yz is always a odd number

therefore it cannot be justified in any case

c.

z

xy

maybe odd number or fraction but ab will always be even.

therefore it cannot be justified.

Relationships given in b and c can't be justified at any cost.