Question 1146316
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Since the new computer works 4 times as fast as the old, when the two work together the new computer does 4/5 of the job.<br>
So in the 15 minutes it takes to do the job, the new computer does 4/5 of the work; that means to do the job alone the number of minutes the new computer would need is 15*(5/4) = 75/4.<br>
ANSWER: 75/4 minutes, or 18 3/4 minutes, or 18 minutes 45 seconds.