ok so their are 3 left if the 3rd prince has 1/2 of what was left from the previous person then theirs 6 mangoes then if the second prince had 1/3 of what was left thats another 3 mangoes so there are 9 mangoes left from the person before then if the first prince had 1/4 that is another 3 added on so their are 12 mangoes left from the queen and if the queen had 1/5 of what was left from the king the king left 15 mangoes and if the king had 1/6 their must have been 18 mangoes at the start
ANSWER : 18 MANGOES