SOLUTION: in a factory, it take 12 machines to pack a box of milk in 5 minutes. How long will it take 8 machines to do the same job ?

Question 1033279: in a factory, it take 12 machines to pack a box of milk in 5 minutes. How long will it take 8 machines to do the same job ?
Found 2 solutions by josgarithmetic, addingup:
Answer by josgarithmetic(39625) (Show Source): You can put this solution on YOUR website!
n, how many machines
r, rate of one machine in BOX per MINUTE
j, how many boxes
t, time

, your work rates rule

Can you form the system of two equations to solve the problem? Your problem description gives a sentence describing the rate and the second sentence is the question.
Answer by addingup(3677) (Show Source): You can put this solution on YOUR website!
12*5 = 60 each machine individually takes 60 minutes
60/8 = 7.5 minutes with 8 machines
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