If we the total weight of the bags is given, and we know both the number of bags of flour and sugar, and we also know the weight of each bag of sugar, then we have to find the unknown, which is X. 30 times X plus 4 times the weight of a bag of sugar would equal 42.6kg. Next step is to put the unknown on one side and the known values on the other side. We have 30 times X equals 42.6 minus 4 times 0.75. To find X we need to divide the value with 30, or to sum up
30X + 4*0.75 = 42.6 30X + 3 = 42.6 X = (42.6 - 3) / 30 X = 1.32 kg
