Good question. Let's try this. How about People per meter squared. The average 2 bedroom apartment in the city near where I live is about 94 square meters. If there were say 100 people at a party in his home, then the number of people per square meter would be 100 / 94 = 1.06 people / square meter.
If however he called those in his home to join him for breakfast and 7 people responded then he would have 7 / 94 = 0.0745 people per m^2 When the number is this small, it might make sense to go the other way. (m^2 per person). 94/7 = 13.4 meters per person. That makes far more sense. It means that every person has 13.4 meters^2 that he could call his own.
It's 369.6
(840X44)/100 = 369.6
We can quickly solve this problem by assigning hypothetical values. Suppose we let Jolie's marbles equal to 100. This would mean that Mary will have 60 since 40% of 100 is 40.
The percentage of all marbles that are Jolie's could be solved by dividing Jolie's hypothetical number of values with the total hypothetical sum of Jolie and Mary's marbles.
ANSWER: 62.5% of the marbles in the bag are Jolie's.