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algebra senior
Problem
On Monday, Millie puts a quart of seeds, of which are millet, into a bird feeder. On each successive day she adds another quart of the same mix of seeds without removing any seeds that are left. Each day the birds eat only of the millet in the feeder, but they eat all of the other seeds. On which day, just after Millie has placed the seeds, will the birds find that more than half the seeds in the feeder are millet?
(A)
(B)
(C)
(D)
Solution
On Monday, day 1, the birds find quart of millet in the feeder. On Tuesday they find quarts of millet. On Wednesday, day 3, they find quarts of millet. The number of quarts of millet they find on day is The birds always find quart of other seeds, so more than half the seeds are millet if , that is, when . Because and , this will first occur on day which is . The answer is .
Final answer
D