Question

Ronita moved 1/3 of the books in her backpack to the kitchen table. Three books were already on the table. There are 5 books on the table now. How many books, b, were originally in Ronita's backpack?

Answer 1

Start with 5 (the total # of books on the table) - 3(the original # of books on the table).  This gives you 2 (the number of books that Ronita placed on the table).  If 1/3b = 2 then you would just multiply both sides of the equation by 3 to find b.  In this case b = 6.