Dude I hope you are joking, because this is just basic math.
Let's suppose the ratio is:
500k - Ps5
500k - PC
According to vgchartz ps5 is at the moment 60.91 Millions and for Xbox is 29.88
So we have
60.91. 29.88
500k X
X = SH 2 Remake Sales on xbox.
Doing basic algebra we get that:
X = 245k