Question 1157967
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The older computer takes 3 times as long as the newer computer; so when they work together the new computer does 3/4 of the job and the older computer does 1/4.<br>
So in completing the job together in 12 minutes, the older computer does 1/4 of the job.<br>
That means that working alone it would take the older computer 4*12=48 minutes to do the whole job.<br>