A boy carries 100N to 500m. How much work is done

Not enough information.

Work is defined as (the sum of) Force(s) dot displacement. So we'd need the direction of the displacement vector.

I guess you could argue that "carry" implies perfectly horizontal displacement. In which case, W = 0J.

In that case, the Force 100N [North] and the displacement is 500m [East / West]. Since the Force and displacement are perpendicular to each other, the dot product is 0, and the boy has done no work.

on the other hand if he carried it 500 m UP, then 100 * 500 = 50,000 Joules

The problem does not say direction so who knows?

To calculate the work done, you need to multiply the force applied by the distance traveled.

Given:
Force (F) = 100 N
Distance (d) = 500 m

The formula for work (W) is:
W = F * d

Plugging in the given values:
W = 100 N * 500 m
W = 50,000 N·m

Therefore, the work done is 50,000 N·m (Newton-meters).