Okay, we know that we have 5 pound, 7 pound and 11 pound boxes as choices. We'll need to find the average. This is a weighted average question. For instance, if there are two 5-pounders, three 7-pounders and one 11-pounder, that's 5*2 + 7*3 + 11*1 = 42kgs / 6 = 7kgs as the average. We know this value will vary depending on different conditions and we need to find the exact answer.
With that in mind, we look at the statements:
Statement I: Okay, cool. We now know that there are exactly twice the number of 5-pound boxes as there are 11-pounders. But will this be enough? For instance, if there is one 11-pounder, we'll get two 5-pounders. If, say, there are three 7-pounders, that'll take the average to 5*2 + 7*3 + 11*1 = 42kgs / 6 = 7kgs. But if there were ten 11-pounders, then there'd be twenty 5-pounders, thus making the average 5*20 + 3*7 + 11*10 = 221 / 37 = ~5.9kgs. Different values. hence, NOT SUFFICIENT.
Statement II: Okay, so, easy. We now know the ratios. This will be enough, because as we increase the count in the same ratio, the average will stay consistent. For instance, as per the 4:2:2 ratio here, we'd get 5*4 + 7*2 + 11*2 = 56 / 8 = 7kgs average, we take the ratios directly.
But if it's 5*40 + 7*20 + 11*20 = 560 / 80 = 7kgs average, we see with the ratio adapting to different values, the answer is still consistent.
Hence, STATEMENT 2 IS SUFFICIENT. B.Bunuel