Ineed on 18 and 19 pls me ily i will marry u i will loveee u for eternity

Oof, this is surely a tough one.  But, if I'm looking at this correctly, than I think you were in the right mindset when trying to figure both of them out.  Like, for #18, think about the formula; P(B|A) = P(A and B)/P(A).  So, based on the question, you can let not rolling a 1 on the blue cube be A, and rolling a 1 on the red cube be B.  Now, personally, I prefer using the decimals when heading into the equations, but I'll convert the product into a fraction for the instruction's sake.  0.02777777778 + 0.13888888889 = 1/6.  1/6 ≈ 17.7%.  You can do the same for #19, the overall outcome would be 5/6, which would be about 83%.  Now, that's just me really attempting my hand at it, I will say, Math is far from my strong suite.  But, in all honesty, I really am doing my best to help (and no, it's not because of what you offered, lol, more rather I want to help people who struggle with the same problems I do).  Anyways, I hope this helps, and if you need more information, or anything, just let me know!  Wish ya the best of luck!!  ^u^

ok

step-by-step explanation:

which expression represents the approximate length of bc?

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