Sophie's space shuttle crew accidentally left her behind on a mysterious planet. She soon realizes that her body is aging much faster on this planet than it did on Earth. There is a proportional relationship between the number of weeks Sophie spends on the planet, x, and the number of years she ages, y.
After 3 weeks on the planet, Sophie's body has aged 6 years.
a. Write the equation for the relationship between x and y.
b. If Sophie stays on the plant 12 weeks, how much will her body age?