$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:

Step-by-step explanation:
step 1
Convert mixed number to an improper fraction

step 2
Using proportion

step 3
Convert to mixed number
