Answer:
11/2 and 19/2
Explanation:
We have to make a system of equations:
1) X + Y = 15
2) X - Y = 4
Working on the first one:
X = 15 - Y
And now let's plug it in the second one:
(15 - Y) - Y = 4
15 - 2Y = 4
2Y = 11
Y = 11/2
Let's substitute this in one of the two equations:
X + 11/2 = 15
X = 19/2