Answer: There are 4 boxes that Raymond buy.
Explanation:
Since we have given that
Number of children will attend the birthday party = 28
Number of favors in a box = 70
Number of party favors get by each child = 10
So, Total number of party favors get by 28 children is given by

So, Number of box they need to buy is given by

Hence, there are 4 boxes that Raymond buy.