Today’s homework is inspired from an email I got from Simran,
I have a mathematical problem, I do not know if it can be solved using excel. So, the question is what is the probability of selecting a mutant cell if the percentage of mutant in the whole population is 0.01 and each cell is dividing 4 times per day,meaning at 2 raised to the power of 4 and the population is say 100,000 and is growing exponentially for 10 days and every day you are selecting, say 1/16 th of the population for the next growth? So, after 10 days, what are the chances that I have different mutants and not clone of the same mutant?
Let me break down the problem for you.
We have a starting population of 100,000 cells (not the A1 kind)- Out of which 1% are Mutant cells
- Each cell becomes 16 cells by end of day
- Naturally, there will be 1 new mutant cell for every 100 new cells produced in such a way.
- At the end of day, we just pick 1/16th of the cells and go for the next day
At the end of 10 days, what portion of total cells are,
- Normal (ie no mutation at all)?
- Clones of original Mutant cells?
- New Mutants?
What you need to do?
Simple. Make an Excel Model to simulate the cell mutation. Your objective is to find answers to above questions thru that model. (Obviously, we can find answers without modeling, but I want to see how we can creatively use Excel to solve a problem like this.)
Once you find a solution,
- Upload your workbook to skydrive or a public website
- You can also email to me at chandoo.d @ gmail.com with subject “mutant ninja turtle”
- Share the link thru comments along with a description of your solution
What if you don’t find mutant cells exciting?
Here is a mutant teddy bear. Enjoy it. (source)
More Excel Homework
If you enjoy excel challenges, then you will love Excel Homework page. It has a bunch of challenging exercises for you.
All the best. Go muse over the mutation problem.
11 Responses to “Fix Incorrect Percentages with this Paste-Special Trick”
I've just taught yesterday to a colleague of mine how to convert amounts in local currency into another by pasting special the ROE.
great thing to know !!!
Chandoo - this is such a great trick and helps save time. If you don't use this shortcut, you have to take can create a formula where =(ref cell /100), copy that all the way down, covert it to a percentage and then copy/paste values to the original column. This does it all much faster. Nice job!
I was just asking peers yesterday if anyone know if an easy way to do this, I've been editing each cell and adding a % manually vs setting the cell to Percentage for months and just finally reached my wits end. What perfect timing! Thanks, great tip!
If it's just appearance you care about, another alternative is to use this custom number format:
0"%"
By adding the percent sign in quotes, it gets treated as text and won't do what you warned about here: "You can not just format the cells to % format either, excel shows 23 as 2300% then."
Dear Jon S. You are the reason I love the internet. 3 year old comments making my life easier.
Thank you.
Here is a quicker protocol.
Enter 10000% into the extra cell, copy this cell, select the range you need to convert to percentages, and use paste special > divide. Since the Paste > All option is selected, it not only divides by 10000% (i.e. 100), it also applies the % format to the cells being pasted on.
@Martin: That is another very good use of Divide / Multiply operations.
@Tony, @Jody: Thank you 🙂
@Jon S: Good one...
@Jon... now why didnt I think of that.. Excellent
Thank You so much. it is really helped me.
Big help...Thanks
Thanks. That really saved me a lot of time!
Is Show Formulas is turned on in the Formula Ribbon, it will stay in decimal form until that is turned off. Drove me batty for an hour until I just figured it out.