(1)(2) Note that the range of values of variables is different;

(3) According to the information given in the figure, the function is determined by the undetermined coefficient method, and then the required value is judged according to the characteristics of the function.

Answer:

Solution:

(1) Figure ① shows that fruits with a wholesale volume of not less than 20kg and not more than 60kg can be wholesale in 5 yuan /kg, while Figure ② shows that fruits with a wholesale volume of more than 60kg can be wholesale in 4 yuan /kg.

(2) From the meaning of the problem:

w={5m(20≤m≤60)

{4m(m>60)、

The function image is shown in the figure.

As can be seen from the figure, when the wholesale volume exceeds 60, the price is within 4 yuan, so when the amount of funds meets 240 < w ≤ 300, the same amount of funds can wholesale a larger amount of this fruit.

(3) Let the daily maximum sales volume be XKG (x > 60), the daily retail price be P, and let X = PK+B. From Figure ②, this function can be obtained by passing through points (6,80) and (7,40) and substituting x=320-40p, so P = (320-x)/.

Sales profit y = x [{(320-x)/40}-4] = [-140] (x-80) 2+160.

When x=80, the maximum value of y = 160, and at this time, p=6, that is, the dealer wants to wholesale 80kg of this fruit, and the daily retail price is set at 6 yuan /kg, and the maximum profit of that day can be 160 yuan.