Answer:
The florist sold 270 flowers.
Explanation:
Since a florist arranged some orchid in bouquets of 20 and some roses in bouquets of 10, and she sells each bouquet of orchid for $ 25 and each rose bouquet for $ 30, and she earns $ 390, if she sell four times as many orchid bouquets as rose bouquets, to determine how many flowers does she sell all together, the following calculation must be performed:
4 x 25 + 1 x 30 = 130
8 x 25 + 2 x 30 = 260
12 x 25 + 3 x 30 = 390
12 x 20 + 3 x 10 = X
240 + 30 = X
270 = X
Therefore, the florist sold 270 flowers.