One frame is equipped with two lenses, and each person can process 102÷2=5 1 pair of lenses every day.

The working speed ratio is 5 1: 68 = 3: 4.

More people will delay doing it.

The number of workers is inversely proportional, that is, 4: 3.

Lens: 28x4/7= 16 people

Framework: 28- 16= 12 people.