What is the revenue?

Question

Dorothy Wagner is currently selling 30 "I ♥ Calculus" T-shirts per day, but sales are dropping at a rate of 5 per day. She is currently charging $7 per T-shirt, but to compensate for dwindling sales, she is increasing the unit price by $1 per day. How fast, and in what direction, is her daily revenue currently changing?

Her revenue is____ at a rate of $____per day

Answer 1

I don't believe that 5 represents a percentage but an actual change per day. If I read correctly

She sells 30 shirts at $7 the first day for a total revenue of $210, then

she sells 25 (5 less) at $8 the next day for a total revenue of $200.

So at this point her revenue is decreasing at $10 a day. This is an average rate of change but this will probably change the next day.

Answer 2

30-5%=30-1.5=28.5*7=$199.5 day1

28.5-5%= 22.8*8=$182.4 2 lost $17.1=.0857 or 8.5714%/daily.