A man caught some fish. The 2 heaviest fish had a combined weight
which was 25% of the total weight of all the fish. The 5 lightest fish had
a combined weight which was 45% of the total weight of all the fish. He
put the 2 heaviest fish in the freezer and ate the 5 lightest fish for lunch.
His cat took all the remaining fish. How many fish did his cat take? Choices:
A) 8 B) 6 C) 4 D) 3 E) 2
Let W be the total weight of all fish the man caught. The fish taken by the cat   had weight 30%W. If the cat took 4 fish or more, then their average weight must have   been at most 7.5%W which is less than the average weight of the 5 lightest fish. If the   cat took 1 or 2 fish, then their average weight must have been at least 15%W which is   more than the average weight of the 2 heaviest fish. Thus, the cat took 3 fish   correct answer 3
<result>D</result>
A man caught some fish. The 2 heaviest fish had a combined weight
which was 25% of the total weight of all the fish. The 5 lightest fish had
a combined weight which was 45% of the total weight of all the fish. He
put the 2 heaviest fish in the freezer and ate the 5 lightest fish for lunch.
His cat took all the remaining fish. How many fish did his cat take?