We had a solution to this problem from someone who didn't give their name or school - but thank you!

From the picture of the scales, the apple must weigh less that the four weights altogether.
If the apple weighs 12 ounces, for the scale to be balanced the weights would have to be 3 ounces each because there are four of them. But we know from the picture that the apple weighs less than the weights put together, so each weight must be more than 3 ounces.
If the apple weighed 15 ounces, then for the scale to be balanced, each weight would be 15/4 ounces which is 3 3/4 ounces. So, for the weights to be heavier than the apple, each one must be more than 3 3/4 ounces.
One pound is 16 ounces and four 4 ounce weights would also weigh 16 ounces altogether so the scale would be balanced.