A four-layer pyramid is being built with each layer having three times as many sandstone blocks as the layer above it. The top layer is a single block. How many sandstone blocks are in the pyramid? Think carefully first, then make a decision:
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There are 1 * 3 = 3 blocks in the second layer. There are 3 * 3 = 9 blocks in the third layer. There are 9 * 3 = 27 blocks in the fourth layer. Thus, there are 1 + 3 + 9 + 27 = 40 sandstone blocks in the pyramid. So, the answer is 40.
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