9x + 10y = 180, x and y are natural numbers, then what can

Question

9x + 10y = 180, x and y are natural numbers, then what can be said about x?
 1] x is always odd 2] x is always even 3] x is odd if y is even 4] None of these

deowl · Answer

Since 10y and 180 are both even, 9x should also be even. So x is always even.

kapslock · Answer

x=(180-10y)/9 = 20 - 10y/9.
For x to be a natural number, 
1. y <= 18
2. y is a multiple of 9.

For all possible values of y (0, 9, 18), x is (20, 10, 0) even.
Hence 2.

gidimba · Answer

X = even 

odd * x + even = even

jaynayak · Answer

X is always even.

Given 9x+10y = 180
Now 10y will always have 0 as the unit digit and 180 has 0 in the unit place hence x can never be odd.
Also 10y is always even....... and E + E = E
Therefore 9x = even and odd * even = even hence x is always even

tl372 · Answer

Ans - 2. X is always even

It doesn't matter what y is since 10y is always even. Since 9x MUST be even as well (in order to add up to 180), x is always even.

ps_dahiya · Answer

9x + 10y = 180

For result to be 180 (an even number) both numbers (9x and 10y) must be either even or both odd. 10y can not be odd in any case. So 9x must be even. For 9x to be even x must be even.

tl372 · Answer

If 9x is even, then x must be even:

9(2) = 18
9(3) = 27

ps_dahiya · Answer

I am sorry that was a typo. I edited that.

9x + 10y = 180, x and y are natural numbers, then what can

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