Answer:
286
Explanation:
If the three-digit number is xyz, then:
x + y + z = 16
y = z + 2
z = 3x
Substitute the third equation into the second:
y = 3x + 2
Substitute this and the third equation into the first:
x + (3x + 2) + (3x) = 16
7x + 2 = 16
7x = 14
x = 2
y = 3x + 2 = 8
z = 3x = 6
The number is 286.