Question

A bag contains some widgets weighing 81 kg. When 2 widgets are removed, the weight of the bag drops to 73 kg. The bag weighs 1 kg when empty. How many widgets are left in the bag after the 2 were removed?

Answer 1

Widget net weight = 80
2 widgets = 8 kg so each widget weighs 4 kg
80/4 = 20 widgets to start with.
After 2 are removed, you have 18