In answering a question on a multiple choice test, a student either knows the answer or the student just guesses. Suppose that the probability that the student knows the answer is 0.75, and the probability the student doesn’t know the answer and guesses is 0.25. Assuming that there are 5 choices for each multiple-choice question, then we take the probability that the student who guesses will be correct is 1/5 = 0.20. What is the conditional probability that the student knew the answer to a question given that the student answered it correctly?

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4

it is x equals 3   plese mark me really need it

step-by-step explanation:

60 for the first and 130 for the second

step-by-step explanation: