First one: (please don't post multiple questions in one post-----you may not get responses to all of them !!)
y = yellow cubes
b = blue = 3y
g= green = 5b = 5(3y) = 15 y
y / (y+3y+15y) = y / 19y = 1/19 chance of getting yellow
Certain is 100% or 1, so E is certain.
Impossible is 0, so A is impossible.
Even is 50%, so C is even.
a is 1/10 because there is one four and a total of 10 cases.
b is 2/10=1/5 because there are two cards with "ones" and 10 total cases.
c is 1-1/5=4/5 because b and c must add to each other.
Last one: the 19.3 and 14.2 dimensions will fit in the box without problems
the WIDTH of the disc case is the questionable one 1.6 cm sixteen of them would need 16 x 1.6 = 25.6 cm
the width of the OUTSIDE of the box is 26 cm.... if the walls of the box are greater than .2 cm each, the interior dimension will not allow for 16 of the disc cases to fit inside.