Question 499104
There are 3 numbers:  x, y, z.
x+y+z=99
y = x-10
z = x-20
.
x + x-10 +x-20 = 99
3x -30 = 99
3x = 129
x = 43
y = 33
z = 23
.
x + y + z = 43 +33 + 23 
43 + 33 + 23 = 99
Check.
.
The greatest of the three numbers is 43.
.
Done.