Please help solve this.

Fredrick designed an experiment in which he spun a spinner 20 times and recorded the results of each spin

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

8litres of paint can cover 129.6 m². how much paint is required to paint an area of 243m²?