Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

This morning, a certain sugar container was full. Since then some of the sugar from this container was used to make cookies. If no other sugar was removed from or added to the container, by what percent did the amount of sugar in the container decrease ?

1) The amount of sugar in the container after making the cookies would need to be increased by 30 percent to fill the container

2) Six cups of sugar from the container were used to make the cookies

We only have one variable as we only need to know the percentage of sugar if we let the total be 100%. There are 2 equations given from the 2 conditions, so there is high chance (D) will be our answer.

From condition 1, if we let the amount of sugar left be X, 1.3X=100%, so this is sufficient.

For condition 2, there is no relationship between percentage and number, so this is insufficient and the answer is (A).

from con 1) and con 2), if one of the conditions is given by numbers and the other is given by ratio (percent,fraction), then the condition with ratio (percent,fraction) value has higher chance of being the answer

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