Question 980744
if 1 tractor ploughs a field in 5.6 hours and another can plough the same field in 2.8 hours. How long would it take if both were working simultaneously to plough the field  
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2.8 is 1/2 of 5.6, equivalent to 2 tractors that take 5.6 hours.
--> 5.6/3 hours together.