The cost of my algebra book is 200% of that of my geometry book. The cost of my geometery book is 4/3 that of my calculus book. If my calculus book costs $21, how much do all 3 books cost together?
Let the Geometry book price = P
The Algebra book = 2P
And the Geometry book = (4/3)Calculus book
The geometry book costs (4/3)*21 = $28
The Algegra book costs 2(28) = $56
21 + 28 + 56 = $105