Answer:
Jacob starts with 32 cookies; Elisabeth starts with 4.
Explanation:
Let x represent the number of cookies Elisabeth starts with. Then Jacob starts with 8x. After the transfer of cookies, we have the relationship ...
2(8x -20) = (x +20) . . . . Elisabeth will have twice the number of cookies Jacob has
16x -40 = x + 20 . . . . . . simplify
15x = 60 . . . . . . . . . . . . add 40-x
x = 4 . . . . . . . . . . . . . . . divide by 15
Elisabeth starts with 4 cookies; Jacob starts with 32 cookies.
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After Jacob gives Elisabeth 20 cookies, he has 12 and she has 24, twice his number.