Every brick in this pyramid contains a number that is the sum of the two numbers in the two bricks below it. What is the value of B?
+538 
(sry if the image is blurry or hard to understand)
(also in the picture I messed up and said the top was 938 and not 978)
225=104+x+y can be simplified to x+y=121. Plugging that into 2x+2y+z=287, we get that z is 45. since we know y+z is 147, y is 102, and solving we get x is 19.
pls correct me if I'm wrong or if I made some sort of mistake
+118609 I think you did that brilliantly. 
I used your method and got the same answer.
+128474 M + N = 978
N =225 + L
M =225 + J
So
M + N = 450 + (L + J)
978 = 450 + (L + J)
L + J = 528
(F + G) = J
(G + H) = 225
(H + I) = L
(H + 147) = L
So
J + 225 + L = 753
(F + G) + (G + H) + ( H + I) = 753
(F + G) + (H + I) = 528
(F + G) + (H + 147) =528
(F + G) + H = 381
F + (G + H) = 381
F + 225 = 381
F = 156
A + B = F
137 + B = 156
B = 19
Just as 4M and Melody found !!!!
P.S. - I really liked this problem ......
