It would be better to buy a dozen for $35.40
Answer:
5 in 12 chance or 42% probability of happening
Remark
The best way would be to make a duplicate of this page and cut out the shapes. Then find out which ones fold into a cube. It would also be the most time consuming.
The second best way is to imagine how each flat surface would fold to make a cube. I think C would and D would. I don't think the other 2 would.
We have 89 ounces of 47% iodine.
We will add "x" ounces of 14% iodine to get a 29% iodine solution.
89 * .47 + .14x = .29 * (89 + x)
41.83 + .14x = 25.81 + .29x
16.02 = .15x
x = 106.80
So, we must add 106.80 ounces of 14% iodine to get a 29% iodine solution.
(for a total of 195.80 ounces)
Source:
http://www.1728.org/mixture.htm