Data Sufficiency (DS) | Re: If x, y, and z are positive integers, is x+y divisible by 5? 1) x+z is

Q1. When the Q says x, y, z are integers, shouldn't we take all as different numbers but all the explanations here have considered x equal to y to reach to the answers. So is it that, unless explicitly defined as unique there is no need to take different values. Because the Q also doesn't say explicitly that x, y, z can take any value.

Q2. Also under the assumption that they are all different, would E still be the right answer, based on the following:
2+8 & 7+8 both divisible by 5 but 2+7
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