How it works
Mr. Glib's Golden Goose Club promised forty coins back for four, in a week. That is ten times more, in just seven days.
Maya asked where the forty coins come from. If ten children each put in four coins, the jar holds only forty.
Paying the first child forty empties the jar, and nine children are still promised forty each. The club needs four hundred coins, so three hundred and sixty are missing.
Coins out can never be more than coins in. A club like this can only pay early members with coins from newer members, so the last members lose their coins.