kevincan wrote:

A set has a single mode of 9 only if 9 occurs more often than any other number. Some sets have several modes, others have no mode.

Then the answer is B = 4

If we take nines 2 times:

Then we have to take all other numbers only once and set will be 9912345678. Sum will exceed 45.

If we take nine three times:

Then we can take any number at a max of 2 times. To minimize the sum repeat the smallest numbers more. Sets are

9991122334 = 43.......................1

9991122335 = 44.......................2

9991122336 = 45.......................3

9991223344 = 46.. EXCEEDS 45.

If we take nine four times:

9999111222 = 45.......................4

9999111223 = 46.. EXCEEDS 45.

We can't take 9 five time or more because sum exceeds 45.

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SAID BUSINESS SCHOOL, OXFORD - MBA CLASS OF 2008