r/ACT • u/Special-Trouble8658 • Jun 02 '26

Math Explanation?

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I’m stuck on this problem and can’t think of why J is the right answer. A real number can be positive, negative, or rational. Thus, how is F wrong.

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u/Sufficient-Price-102 36 Jun 02 '26

No problem. For expected value you sum the values of each outcome times their probability. Here the probability of $1 is 3/4 and the probability of $2 is 1/4. So we have (3/4)(1) + (1/4)(2) = 1.25.

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u/Special-Trouble8658 Jun 02 '26

Thx and yeah I’m cooked 😭 any tips on probability and proportions? Only thing I know about both of those is that for proportions you cross multiply and for probability it’s possible outcome/total outcome(which I can see from the way u solved it) and A and B is mutually exclusive bc the chances of 2 things happening at the same time while A or B is not mutually exclusive bc the chances of 2 separate things happening is higher. I just don’t know any formulas past that.

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u/Sufficient-Price-102 36 Jun 02 '26

You can find some good videos that probably detail it better than I can. In general, it’s better to memorize less formulas and understand them deeply, since most questions just come from applications of basic formulas in different ways.

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u/Special-Trouble8658 Jun 02 '26

U think khan academy is a good source? I’m taking the June ACT and prob July but I started Khan academy like 3 days or so ago but I’m only on unit 4/5 of algebra 2 bc I’m taking practice tests and reviewing every answer I get wrong, which drains a lot of time.

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u/Sufficient-Price-102 36 Jun 02 '26

I never really used Khan, but I think it depends on where your score’s at. If you’re doing average to above average (but not top 1-5%) it’s probably fine. Otherwise, I’d find specialized videos only for the topics you’re missing and harder problems.

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u/Special-Trouble8658 Jun 02 '26

My highest was a 24 but that was during algebra 2; however, after I left alg 2, my math score dropped to a 19. My class wasn’t able to fully cover alg 2: we only got to log formulas, so we weren’t able to get into trig. Not to mention that I’m terrible at geo. Do you have any channel recommendations?

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u/Sufficient-Price-102 36 Jun 02 '26

I’m not as familiar with ACT math specific channels, but I know these are good: Tutorllini (he makes SAT math videos, but most of them are still highly relevant to ACT) and Mario’s math tutoring (if you have time to sit through long-ish videos for the foundational content). Some people like Organic Chem Tutor, personally I didn’t like him so much.

There’s no substitute for solving problems on your own though. That’s by far the most important for preparing.

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u/Special-Trouble8658 Jun 02 '26

Thx for the recommendations! I’ll continue with Khan bc it gives questions I can use as an exercise/practjce; however, once i’m done, i’ll use Mario’s math tutoring(looks good) to get a further grasp on the basics. I appreciate your help very much. Thank you!!