Answer:
81
Step-by-step explanation:
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Use the exponent property regarding a power to power. When you have a power to power, you multiply both powers. In this case, you will get 7^-6. That is equivalent to the first option. I hope this helped, though it is a bit late xD.
Let's name all the purchases "x"
so

of them were stuffed animals, and out of that

were bears.
to get the results we have to multiply the fraction of bears by the fraction of the stuff animals:

.
and now we simplify:

=

and this is the answer!
<span>first stack = 12 blocks second stack = 12 + 3 = 15 blocks third stack = 15 - 7 = 8 12 + 15 + 8 = 35 blocks
So: D XDD
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