Answer:
120/400 of the baseball gloves were left handed.
Step-by-step explanation:
Firstly, multiply 30% and 400 (just 30 x 400)
Secondly, with your solution (12,000), divide it by 100 (because of the percentage)
Lastly, you get your answer which is: 120 out of the 400 baseball gloves were left handed.