Answer:
Probability = 0.58
Step-by-step explanation:
This problem is solve by using Baye's Probability.
Let P(A) = Probability that operator attended training course = 50% = 0.5
P(B) = Probability that operator not attended training course = 50% = 0.5
Also P(Q) = Probability that operator meet their production quotas
Then, P(Q|A) = 90% = 0.9
P(Q|B) = 65% = 0.65
P(A|Q) = ?
Then by Baye's Theorem,

⇒ 
⇒ P(A|Q) = 0.58
which is required probability.
Consider the polynomial identity (difference of squares):
(x+y)(x-y) = x² - y²
Set x =7 and y = 2 to obtain
(7+2)*(7-2) = 7² - 2²
9*5 = 49 - 4
45 = 49 - 4
This is the result required, obtained by using difference of squares.
Answer: Difference of squares.
a. The marginal densities

and

b. This can be obtained by integrating the joint density over [0.25, 1] x [0.5, 1]:

Answer:
see details.
Step-by-step explanation:
Graphs from question not yet uploaded, so read attached graph to make a match.