Revenue to a producer of a good or service will vary with the price and quantity demanded. Suppose a restaurant found that they 100 pizzas are demanded when price is $8. And 80 pizzas are demanded when the price is $11 what is the total change in revenue. If the change is negative [the restaurant has less revenue) the demand for pizza is elastic. if the change is positive the demand for pizza is inelastic. Record your answer with the appropriate positive or negative sign