or
or
Hints: Look at the answer, only A has 30 and 20, 30 + 20 = 50, which is the answer.
Alternatively, let the two parts be x, y ; so x + y = 50
1/x + 1/y = 1/12
(y + x)/xy = 1/12
50 /xy = 1/12
xy = 600
x( 50 - x) = 600
50x - x2 = 600
x2 - 50x + 600 = 0
(x - 30) (x - 20) = 0
x = 30, 20
