GMAT Club Official Solution:Last season, a football team scored 35 more goals than it conceded. Was the difference between the number of goals the team scored and the number of goals it conceded greater this season than it was last season?Let last season’s numbers be:
s = goals scored
c = goals conceded
We are told:
s - c = 35
We need to know whether this season’s difference was greater than 35.
(1) This season, the team scored 10% more goals than it scored last season.
So this season’s goals scored = 1.1s. But we do not know this season’s goals conceded, so we cannot determine this season’s goal difference. Not sufficient.
(2) This season, the team conceded 20% more goals than it conceded last season.
So this season’s goals conceded = 1.2c. But we do not know this season’s goals scored, so we cannot determine this season’s goal difference. Not sufficient.
(1) + (2) This season’s goal difference would be 1.1s - 1.2c. So, we need to know whether 1.1s - 1.2c > 35. Since s - c = 35, substitute s = c + 35 into the question:
Is 1.1(c + 35) - 1.2c > 35?
Is 1.1c + 38.5 - 1.2c > 35?
Is 35 > c?
So the answer depends on last season’s number of goals conceded.
Example 1: If c = 25, then s = 60. This season’s difference = 1.1(60) - 1.2(25) = 66 - 30 = 36, which is greater than 35.
Example 2: If c = 45, then s = 80. This season’s difference = 1.1(80) - 1.2(45) = 88 - 54 = 34, which is less than 35.
So even together, the statements are not sufficient.
Answer: E.