Answer:
45
Step-by-step explanation:
The ratio of x and y is 8:3 and the value of them added together is 99. The value of the ratio is 11. 11 dividing 99 gets 9, therefore to get the value of x and y, we multiply 8 by 9 for x and 3 by 9 for y.
8 · 9 = 72 and 3 · 9 = 27 so now we just subtract them. 72 - 27 = 45, so
x - y = 45. If you only wanted the value of x and y and I misread it, I'll state it again: x = 72, y = 27
Hope this helps! :D