Steve works at an apple orchard and is paid by the bushel

An intuitive approach, with few or no written equations, might prove useful here.

The question is asking how many bushels of apples Steve picked yesterday, and the statements mostly just tell us about money, with no mention of the variable y used in the stimulus.

1) If Steve was paid $180 yesterday, he might have gotten paid $180 for one bushel, or $90 each for two bushels, etc. Insufficient.

2) Steve's total of $240 represents 10 more bushels than yesterday. Ignoring statement 1 for the moment, this means that today he could have picked 12 bushels @20 each, 80 bushels at $3 each, etc. The only real difference between this information and that offered in statement 1 is that we know he picked at least 10 apples today. Since that just tells us he picked at least 0 apples yesterday, that's not exactly revealing information. Insufficient.

1&2) Putting the two statements together, we know that the 10 extra bushels Steve picked today were worth $60 in pay. But is this at the rate of y or 1.5y? We don't have to do the calculations to know that we will get two different results. Insufficient.

I hope this helps those looking for a shortcut!