Divide the number of computers produced by the corresponding number of days that it took to produce them in order to find the unit rate of computers produced per day.
Since 36 computers were produced in 3 days, then divide 36 over 3:
Therefore, the unit rate is 12 computers per day.
Notice that the same number is obtained if we use a different pair of data. Since 48 computers are produced in 4 days, if we divide 48 by 4 we still get that the unit rate is 12 computers per day.
Therefore, the unit rate of computers produced per day, is: