I think you should try studying a little every day.
Answer:
I don't know why it didn't occur to us earlier. ... The circulation and readership of POPULAR SCIENCE grew sharply after the ... And what a job it turned out to be! ... If so, write and tell me about anything you feel should have been included, and why. Two more things: First, I'd be pleased to know your reactions to the idea.
Explanation:
After 6 months.
Difference in their original number of stamps: 80-56=24
Difference in the number of stamps they receive each month: 12-8=4
Number of months to have same number of stamps: 24/4=6
They will each have 6x12+56=128 stamps