Of the 1,000 students in a local college, 420 own brand x mobile phones and 580 own brand y mobile phones. of these students, 80 own both brands of mobile phones. find the probability that a student chosen at random has a brand x mobile phone given that he has a brand y mobile phone.

Step-by-step explanation:

We know that the formula to find the conditional probability of A given that B is given by :-

Let A be the event that students own mobile phones  of Brand X and B be the event that students own mobile phones  of Brand Y.

Then ,

Then , the required probability will be:-

the line of

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.