Step-by-step explanation:
No. of stamps bought= 6
No. of stamps sold= 4
Difference, No. of stamps left with her= 2
She bought 2 sets of 5 stamps.
So, no. of stamps she bought= 10 stamps
Stamps she has overall= 10+2= 12 stamps
Dividing it into 3 groups= 12/3= 4 stamps
Answer: She put 4 stamps in each book.
Hope it helps u! :)