Question

If an exit sign is hanging from the ceiling by three chains each of which has a tension of 15N what is the weight of the sign

Answer 1

The weight is 45 N, because the three chains hold the sign, and each contributes 15 N.

Notice that the mass would be the weight/acceleration of gravity, m = 45/9.8 kg. But they ask the weight (force, so Newtons)