Let’s keep this discrete.

Gabriellebirchak/ October 22, 2019/ Late Modern History, Modern History, Uncategorized

Today’s pod and blog are about one of the many facets of Dis­crete Mathematics. 

Here are two solu­tions to the 3‑gallon/ 5‑gallon jug problem. 

First Solution

The first solu­tion is a 6‑step solution:

1. With two emp­ty jugs, I would fill the 5‑gallon jug. Now the 5‑gallon jug now has 5 gal­lons of water. 

2. I would pour the 5‑gallon jug into the 3‑gallon jug, which now means I have the 3‑gallon jug filled with 3 gal­lons of water and the 5‑gallon jug filled with 2 gal­lons of water. 

3. Then I would pour out the 3‑gallon jug, which leaves me only two gal­lons of water in the 5‑gallon jug.

4. Then I would pour the two gal­lons of water from the 5‑gallon jug into the 3‑gallon bot­tle. Then I would have 2 gal­lons in the 3‑gallon bot­tle and an emp­ty 5‑gallon jug. 

5. Then I would fill the 5‑gallon jug com­plete­ly full. That gives me 5 gal­lons of water in the 5‑gallon jug and 2 gal­lons of water in the 3‑gallon jug. 

6. Then I would pour water from the 5‑gallon jug into the 3‑gallon jug. That gives me 3 gal­lons of water in the 3‑gallon jug and 4 gal­lons of water in the 5‑gallon jug. There are the 4 gal­lons that I need!

Second Solution

Here is the sec­ond solution:

1. With two emp­ty jugs, I would fill the 3‑gallon jug with 3 gal­lons of water. 

2. Then I would pour the 3 gal­lons of water into the 5‑gallon jug. Now the 3‑gallon jug has no water, and the 5‑gallon jug has 3 gal­lons of water.

3. Then I would fill the 3‑gallon jug. Now the 3‑gallon jug has 3 gal­lons of water, and the 5‑gallon jug has 3‑gallons of water.

4. Then I would pour the water from the 3‑gallon jug into the 5‑gallon jug. Now the 3‑gallon jug has 1 gal­lon of water, and the 5‑gallon jug has 5 gal­lons of water. 

5. Then I would emp­ty the 5‑gallon jug. Now the 3‑gallon jug has 1 gal­lon of water, and the 5‑gallon jug is empty.

6. Then I would pour the 1 gal­lon from the 3‑gallon jug into the 5‑gallon jug. Now the 3‑gallon jug is emp­ty, and the 5‑gallon jug has 1 gallon.

7. Then I would fill the 3‑gallon jug full. Now the 3‑gallon jug has 3 gal­lons, and the 5‑gallon jug has 1 gallon. 

8. Then I would pour the water from the 3‑gallon jug into the 5‑gallon jug. There are the 4 gal­lons that I need!! 

How not to Die Hard

Math­ologer has a great video here that cre­ates a process for under­stand­ing how to solve this prob­lem. This is great because tech­ni­cal­ly, the method pro­vides a way for one to solve any two-buck­et prob­lem, giv­en that the two buck­ets are dif­fer­ent sizes. Please check it out and have some fun with this!

Books

And if you are inter­est­ed in learn­ing more about Dis­crete Math, I want to rec­om­mend two of my absolute favorite col­lege text­books on Dis­crete Math. The first, titled Dis­crete Math­e­mat­ics with Appli­ca­tions is one of the most straight­for­ward col­lege text­books in this sub­ject to under­stand. It is writ­ten by Dr. Susan­na S. Epp. Dr. Epp is a Pro­fes­sor Emeri­ta of Math­e­mat­i­cal Sci­ences at DePaul Uni­ver­si­ty in Chica­go. I bought a used ver­sion of this as an under­grad, and it became my favorite math bible. 

The sec­ond book is Math­e­mat­ics for Infor­ma­tion Tech­nol­o­gy by Dr. Alfred Bas­ta, Pro­fes­sor Nadine Bas­ta, and Pro­fes­sor Stephon DeLong. Dr. Bas­ta was my pro­fes­sor in my under­grad stud­ies (Hi Dr. Bas­ta!), and this book is real­ly a fun read, full of puz­zles and math prob­lems, and as a math nerd, I found it enjoy­able to the last page. 

Final­ly, McClane is com­ing back next year! Until 2020, I’ll be catch­ing up on all the Die Hard movies!

So, until next week, yippee ki-yay and carpe diem!

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