Can you provide an in-depth solution for: Doris earns $20 per hour by babysitting. She needs to earn at least $1200 for her monthly expenses. She can babysit for 3 hours every weekday and 5 hours on a Saturday.  How many weeks does it take for Doris to earn enough to cover her monthly expenses?Hey there, could you help me solve this math problem: Doris earns $20 per hour by babysitting. She needs to earn at least $1200 for her monthly expenses. She can babysit for 3 hours every weekday and 5 hours on a Saturday.  How many weeks does it take for Doris to earn enough to cover her monthly expenses?