Answer:
Part A:
The probability that all of the balls selected are white:

Part B:
The conditional probability that the die landed on 3 if all the balls selected are white:

Step-by-step explanation:
A is the event all balls are white.
D_i is the dice outcome.
Sine the die is fair:
for i∈{1,2,3,4,5,6}
In case of 10 black and 5 white balls:






Part A:
The probability that all of the balls selected are white:


Part B:
The conditional probability that the die landed on 3 if all the balls selected are white:
We have to find 
The data required is calculated above:

Just comparing your (x, y) points to the values on the table, it looks like b) would be the quick answer. Since it states under the table to use average values within each range.
So for x=62 (the weight), we have y=122 (the iron count) which would be the average of the range between 115 and 129.
Similiarly, x=70 corresponds to y=146, which is the average of 139 and 153.
You could take the average values of your highest and lowest iron count ranges compare them to the max-min weight to get your slope. Looks like it would be (155-112)/(73-58)= 43/15= 2.8666 repeating. That would make sense with the slope in the equation listed in b) as well.
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The value of t that makes the factor e^(.032t) have the value of 2 can be found using logarithms.
2 = e^(0.032t)
ln(2) = ln(e^(0.032t)) = 0.032t
t = ln(2)/0.032 ≈ 21.66
It would take 21.66 years for the cost to double.