The picture above shows four equal weights on one side of the scale and an apple on the other side.
What can you say that is true about the apple and the weights?
If the apple weighs $180g$, how heavy must one weight be?
If the apple weighed $375g$, how heavy would one weight be?
If the apple was a giant one and weighed a full kilo and the weights were each $250g$, what would the scale look like? How do you know? Can you prove it?