If there are 50 rows of flowers with 400 flowers per row, there are 50*400 = <<50*400=20000>>20000 flowers in the garden,
Mr. Wells cuts flowers from 60% of the flowers, which is 60/100*20000 = <<60/100*20000=12000>>12000 flowers.
The total number of flowers remaining in the garden is 20000-12000 = <<20000-12000=8000>>8000
#### 8000