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How can you decide witch operations to use to slice a two step equation

Determine the fraction of total interest owed. after the fourth month of a 12-month loan: the numerator is: {(n + ) + (n + ) + (n + ) + (n + )} = , and the denominator is: {(n) + (n + 1) + + (n + )} = . therefore, the fraction is numerator/denominator (to the nearest tenth) =

Manny bought 12 pounds of vegetables at the supermarket. 75% of the vegetables were on sale. how many pounds of vegetables were not on sale? 98 points : )