brastilava:Hi, please help in following question:
At a prize-giving ceremony, prize-winners could invite either one or both of their parents to attend. The ratio of the number of prize-winners to the number of parents who attended was 8:11 and 3/8 of the prize-winners bought only one parent. What fraction of the prize-winners did not have any parents attending the ceremony?
Prize Winners = 8 units
Parents = 11 units
Out of prize winners (8 units), there are 3 groups:
Brought 1 parent = 3/8 of 8 units = 3 units; 3 units x 1 parent = 3 units of parents
Brought both parents } 8 units - 3 units
Did not bring parents } = 5 units
Now, looking at the parents:
11 units - 3 units = 8 units
8 units of parents belong to those who brought BOTH parents.
Prize Winners (brought both parents & did not bring parents):
Brought both parents: 8 units of parents divide by 2 parents per prize winner = 4 units of prize winners
5 units - 4 units = 1 unit of prize winners did not bring parents
1 out of 8 prize winners did not bring their parents. (Ans: 1/8)