If 50 people paid a total of $110 for tickets to attend a certain high school play and spent a total of $100 for refreshments at intermission, how many adults attended the play?
Some adults and kids totaling 50 attended the school party, that is A+K=50.What is A?
(1) Each adult who attended the play paid $3 for tickets, and each child who attended paid $1 for tickets.
We can get the answer by weighted average method as we have two averages 3 and 1, and combined average is 110/50 or 2.2
Sufficient to get value of A and K.
(2) Each adult who attended the play spent $2 for refreshments at intermission, and each child spent $2 for refreshments at intermission.
We can use weighted average method only if averages were different. Here everything is 2.
Average of everyone is 2, so the total is 2*50=100, which we already know.
Insufficient
A
Method for finding values:
(1) Weighted average method: \(\frac{3-2.2}{3-1}=\frac{number of kids}{total}...K=50*\frac{0.8}{2}=20...A=50-20=30\)
(2) Weighted average method: \(\frac{2-2}{2-2}=\frac{number of kids}{total}...\). It just tells us that 2*A+2*K=100 or A+K=50, something we already know.