Answer:
The florist needs to order me 7 more red flowers then there will be enough for 21 bouquets, with no flowers left over.
Explanation:
If she had given back 50 of the others then the florist would classify that as left over stock, so she would need to order and ask for 7 more.
1050 / 50 = 21
140/7 = 20
Get on the phone and get me 7 red roses.