a rather hard one

L = labor
M = materials
P = profit

500,000 = L + M + P

Is P>150,000?

Statement 1:
L + M = 3M
L = 2M

500,000 = 2M + M + P
500,000 = 3M + P

if M = 150,000, P < 150,000
if M = 50, 000, P > 150,000. Insufficient.

Statement 2:
P > L

P > 500,000 - M - P
2P > 500,000 - M
P > 250,000 - M/2

again, no info on M. Insufficient.

Both statements together:
L = 2M
P>L

500,000 - L - M > L
500,000 > 2L + M
500,000> 5M
M < 100,000

so at most, M can be 99,999.99. Lets round this to 100,000.

500,000 = L + M + P
500,000 = 3M + P
P = 200,000

we can firmly conclude that P>150,000. Sufficient.

Choose C.

-BM-

Great explanation by BM!!!

great Blue Mentor.