3. Juan goes to the book fair where paperback books are $6 and hardbackbooks are $8.50. Juan buys four paperback and 3 hardback books. He payswith a $50 bill.3a. Edward wrote the expression below to represent how much changeJuan should get back. However, there is something wrong with his work.Explain the mistake and help Edward fix the expression. *50 - 6 x 4 + 8.5 x 33b. How much change does Juan get back?