Swindon College has two econometrics classes, and nobody is enrolled in both. In the morning class, 60% of those enrolled are undergraduate students, and the other 40% are graduate students. In the afternoon class, 45% of those enrolled are undergraduate students. If half of those enrolled in an econometrics class at Swindon are undergraduate students and $\frac{3}{10}$ are graduate students, what fraction of those enrolled in the afternoon class are neither undergraduate nor graduate students?

This one looks like a standard mixture setup but the wording about the 'neither' group tripped me up at first. I had to read it twice to realize the neither students only exist in the afternoon class.

705-805? This felt more like a 650 to me honestly. Once you realize you can just pick numbers for total enrollment the algebra is pretty clean.

The key for me was noticing that the two groups 1/2 and 3/10 leave 1/5 of ALL students unaccounted for, and that 1/5 has to live entirely in the afternoon section. From there it's just comparing the afternoon's undergrad share.

Anyone else try to set this up with two variables and get buried in equations? Picking a total of 100 students made it way faster for me.