Q: "A boy wearing a bike helmet, jeans, and a striped shirt and a girl wearing a green shirt and jeans ride bikes with training wheels down a sidewalk." Does this mean that "There are children outdoors"?
A: yes

Q: "Four people checking out and possibly repairing one of their bicycles." Does this mean that "The four people are all men."?
A: it is not possible to tell

Q: "Three men are building a roof." Does this mean that "A kid plays basketball with his friend."?
A: no

Q: "A woman in a purple shirt playing an instrument." Does this mean that "A woman is playing an instrument."?
A:
yes