The numbers \(x_1,x_2,x_3,x_4\) are chosen at random in the interval \([0,1]\) Let \(I\) be the interval between \(x_1,x_2\) and let \(J\) be the interval between \(x_3,x_4\) Find the probability that intervals \(I,J\) both have length greater than \(\frac{3}{4}\).
Ok, so this implies that \(x_2-x_1>3/4\), same thing for the other pair.
We'll just assume that the numbers go from least to greatest.
This means that \(x_1<1/4\), which is 1/4 chance, times the chance that \(x_2>3/4\), which is also 1/4. multiplying, we get 1/16, which we multiplu by 2 since they don't have to go from least to greatest, we just assumed. This gives us 1/8.
We do the same for \(x_3,x_4\) and get the same result. Adding these together will give us our final answer, \(\fbox{1/4}\)
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