Bunuel
What is the average (arithmetic mean) number of runs per game scored by The New York Yankees last season ?
(1) Last season, The New York Yankees played 160 games
(2) Last season, The New York Yankees scored four runs per game in exactly 1/5 of their games, five runs per game in exactly 3/4 of their games, and nine runs per game in exactly 1/20th of their games.
We need to answer the question:
average = sum of terms/number of terms = ?
Statement One Alone:=> Last season, The New York Yankees played 160 games.
number of terms = 160
We can’t determine the average because we don’t know the sum of terms. Statement one is not sufficient. Eliminate answer choices A and D.
Statement Two Alone:=> Last season, The New York Yankees scored four runs per game in exactly 1/5 of their games, five runs per game in exactly 3/4 of their games, and nine runs per game in exactly 1/20 of their games.
Let’s check what total fraction of the games we have information about:
1/5 + 3/4 + 1/20 = 4/20 + 15/20 + 1/20 = 20/20 = 1
We see that we have sufficient information to determine the average number of runs per game scored as a weighted average:
average = (1/5)4 + (3/4)5 + (1/20)9
Statement two is sufficient.
A
nswer: B