Find two numbers if their sum is 6.1 and their difference is 1.6

For this case, the first thing we must do is define variables:
 x: unknown number (1)
 y: unknown number (2)
 We now write the equations that model the problem:
 their sum is 6.1:
 [tex]x + y = 6.1 [/tex]
 their difference is 1.6:
 [tex]x - y = 1.6 [/tex]
 Solving the system we have:
 We add both equations:
 [tex]x + x = 6.1 + 1.6 2x = 7.7 x = 7.7 / 2 x = 3.85[/tex]
 Then, we look for the value of y using any of the equations:
 [tex]x - y = 1.6 y = x - 1.6 y = 3.85 - 1.6 y = 2.25[/tex]
 Answer:
 The numbers are:
 [tex]x = 3.85 y = 2.25[/tex]