The data shows the number of miles troy ran last week

Ineed if you could explain and give me the answer you! this needs done

Abag contains 4 red, 7 blue and 5 yellow marbles. event a is defined as drawing a yellow marble on the first draw and event b is defined as drawing a blue marble on the second draw. if two marbles are drawn from the bag, one after the other and not replaced, what is p(b|a) expressed in simplest form? a. 7/16 b. 7/15 c. 14/16 d. 14/15

Solve x+3y=6 and 4x-6y=6 by elimination . show work !