The problem of quadratic function The relationship between the price and time t (unit: day) of a certain commodity in the supermarket in the recent 30 days is (T + 10) yuan, and the relationship between the sales volume and time t is (35-t), where t is greater than 0 and less than or equal to 30, and it is an integer. When does the commodity get the maximum daily sales amount? What is the maximum value?

The problem of quadratic function The relationship between the price and time t (unit: day) of a certain commodity in the supermarket in the recent 30 days is (T + 10) yuan, and the relationship between the sales volume and time t is (35-t), where t is greater than 0 and less than or equal to 30, and it is an integer. When does the commodity get the maximum daily sales amount? What is the maximum value?

Sales = (T + 10) (35-t) = - T & # 178; + 25t + 350
=-(t-25/2)²+506.25
When t = 12 or 13, the maximum value is 506 yuan