Because only A and C have purple flowers, the pot number of C is (3750-25x)/25, which means 150-x after using 3750 flowers.

Used 2900 red flowers.

So15x+10y+10 (150-x) = 2900.

Simplify 5x+ 10y= 1400, and then simplify x+2y=280.

Huang Huayi * * * used 24x+12y+18 (150-x) and the simplified 6x+ 12y+2700.

Given x+2y=280, then 6x+12y = 6 (x+2y) =1680.

Therefore, the chart method of Huanghua 6x+12y+2700 =1680+2700 = 4380 is red, yellow and purple.

A 15 24 25

B 10 12

C 10 18 25

A+C =3750÷25= 150 ① formula

15a+10b+10c = 2900, that is, 3A+2B+20C =580 ② formula.

①+② = 4A+2B+3C =580+ 150=730。

Huanghua = 24a+12b+18bc = 6× (4a+2b+33b) = 730× 6 = 4380.