Eliza bought a day pass to rent a bike in the city. The day pass costs $40 from 9 a.m to 7 p.m. There is a additional fee of $4 per quarter hour if she returns the bike after 7 p.m. Eliza has $50 and plans to return the bike at 8:15 p.m . Does Eliza have ebough money ? Explain using an equation. When should she return the bike?