Mother, daughters and apples
We must solve this problem backwards.
When giving the third daughter, the apples are gone. So at that moment the mother only had 1 apple, ie:
half apples (0.5) + half apples (0.5) = 1 apple
Before giving the second daughter:
(1+0,5) * 2 = 3 apples in the basket
Before giving the first daughter:
(3+0,5) * 2 = 7 apples in the basket
Answer: The basket contained 7 apples.
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