Question 13955
If the toothbrush wears down to half of its length in 90 days linearly, then it will wear out the rest of the way in another 90 days, for a total of 180 days to wear completely out.  


Since 2 weeks and 4 days is a total of 18 days, that would be 1/10 of the total life of the toothbrush.  This means that 10% has been used up, and 90% remains.  I would say the answer is E) 9/10.


R^2 at SCC