$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
106 sio so you multiply first
1+1+2+3+4+5+6×15
1+1+2+3+4+5+90
then you add all of them then it will be 106
Here is my work for the problem. Hope this helps!
I think it is 2.5 but not sure correct me if i am wrong