Q:

ListPlot using data from a .txt file

I have a .txt file. In this file, there are four columns where the data of the first and the last column are important for me. In fact, I want to plot the last column versus the first one (density versus radius). How can I do it with Mathematica?
Here is a little part of it:
0.0 0.00149641273911    1.0 0.00148351904051
0.05    0.00149641273911    1.0 0.00148351904051
0.1 0.00299053929892    2.0 0.00148232332057
0.15    0.00598107859762    4.0 0.00148232332057
0.2 0.0089667320496 6.0 0.0014815018355
0.25    0.00895899924806    6.0 0.00148026219129
0.3 0.0178884006853 12.0    0.00147779468805
0.35    0.0149055941882 10.0    0.00147763274807
0.4 0.00892134647063    6.0 0.00147358477342
0.45    0.0237816339041 16.0    0.00147266475701
0.5 0.0267197078908 18.0    0.00147046950329
0.55    0.0133373226818 9.0 0.00146804990797
0.6 0.019229311372  13.0    0.00146396790859
0.65    0.0266098075851 18.0    0.00146274986023
0.7 0.0147447671119 10.0    0.0014582820985
0.75    0.0220696757713 15.0    0.00145453550223
0.8 0.0279204483924 19.0    0.0014522885186
0.85    0.0219620881693 15.0    0.00144688290853
0.9 0.0305841793211 21.0    0.00144076172379
0.95    0.0261777601237 18.0    0.00143840316003
1.0 0.0159427605594 11.0    0.0014320712915
1.05    0.0388780680901 27.0    0.00142473696791
1.1 0.0373336347174 26.0    0.0014209691104
1.15    0.0157011916107 11.0    0.0014124551978
1.2 0.0326389667079 23.0    0.00140594862015
1.25    0.0424536264102 30.0    0.00140142104673
1.3 0.0239562027908 17.0    0.00139390835155
1.35    0.0322186571433 23.0    0.00138511993195
1.4 0.0391244630839 28.0    0.00138178132691
1.45    0.0263499097266 19.0    0.00137240383193

A:

With a default Import path:
import = Import["data.txt", "Table"];
ListPlot[import[[All, {1, 4}]]]

A:

Assuming the data.txt file is in the same folder of the MMA notebook:
data=Import[NotebookDirectory[] <> "data.txt", "Data"][[;; , {1, 4}]]

ListPlot[data]

EDIT:
if you want to multiply each column by a number "n" and "m", see code below:
Transpose[{data[[;; , 1]]*n, data[[;; , 2]]*m}]

There are many other ways of doing it, some faster than others: for more details see this link:
Multiplying x and y coordinates with different scalars?

