Answer:
28
Explanation:
x = medals won by Russia
y = medals won by China
z = medals won by United States
Write a system of equations:
x + y + z = 96
z = y + 4
x + z = 2y
Substitute the second equation into the first and third:
x + y + y + 4 = 96
x + y + 4 = 2y
Simplify:
x + 2y = 92
x + 4 = y
Substitute for y:
x + 2(x + 4) = 92
x + 2x + 8 = 92
3x = 84
x = 28
Russia won 28 medals.
Which means China won 32 medals and the US won 36 medals.