Final answer:
The original weight of the radioactive material, given the formula W=1500 x (0.993)ʸ grams, is found to be 1500 grams when t equals zero.
Step-by-step explanation:
The original weight of the radioactive material can be found by examining the given decay formula W=1500 x (0.993)ʸ grams, where W represents the weight of the substance after t years. The original weight is the value of W when t=0. Thus, when we replace t in the formula with 0, we get W=1500 x (0.993)⁰ grams. Since any number raised to the power of 0 is 1, the original weight (W) is 1500 grams.