Money related questions in linear equations

Lessons

1. Andy is paid based on a base salary plus commission for selling furniture. One week he sold $5000 worth of furniture and was paid $550, another week was paid $450 on sales of $3500.
   a) What is the rate of commission Andy earns?
   b) What is his weekly base salary?
   c) How much he earn if he sold $7000 dollars worth of furniture one week?
2. Tickets are sold at $20 for adults and $10 for students. If the revenue from ticket sales was $12000 and 740 people attended the play; how many adult tickets were sold?
3. The cost to insure jewellery is a fixed amount plus a percentage of the value of the jewellery. It costs $32 to insure $1000 worth of jewellery or $44.50 to insure $3500 worth of jewellery. What is the fixed amount to insure jewellery?