$7.9 cost of one pack
10 packs cost is $79
She pays $29 + Voucher
From the total $79 we substract the $29 she paid with cash or card.
79-29=50
So the value of the voucher is $50
PS: celia should cut on chocolate. Not healthy for her :)
Answer:
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Step-by-step explanation:

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Answer:

Step-by-step explanation: