Answer:
528
Explanation:
Surface area of bottom block + Surface area of top block - 2(Shared surface area)
Bottom block: 2(10*12) + 2(5*12) + 2(5*10) = 240 + 120 + 100 = 460 square inches
Top block: 2(2*2) + 4(2*8) = 8 + 64 = 72 square inches
Shared surface area = 2*2 = 4 square inches
Plugging into our formula:
460 + 72 - 4 = 528 square inches