A technology specialist studied the relationship between time spent on social media and age. One observation found that a 50-year-old person spends 8 hour per week on social media. A second observation showed that a 20-year-old person spends 20 hours per week on social media. Assuming time spent per week on social media T (in hr) is a linear function of age a (in yr), find a linear model of this event.

Use the model to find the age (in yr) of a person who spends 10 hours per week on social media.