diff --git a/chapter.mk b/chapter.mk
index 8a0e56e..d9aa865 100644
--- a/chapter.mk
+++ b/chapter.mk
@@ -8,7 +8,8 @@ PYPDFFILES=$(PYFILES:.py=.pdf)
 pythonplots : $(PYPDFFILES)
 
 $(PYPDFFILES) : %.pdf: %.py
-	python $<
+	echo $$(which python)
+	python3 $<
 
 cleanpythonplots :
 	rm -f $(PYPDFFILES)
diff --git a/scientificcomputing-script.tex b/scientificcomputing-script.tex
index 22bbed8..03d8c8e 100644
--- a/scientificcomputing-script.tex
+++ b/scientificcomputing-script.tex
@@ -67,7 +67,7 @@
 \lstset{inputpath=regression/code}
 \include{regression/lecture/regression}
 
-\setboolean{showexercisesolutions}{true}
+\setboolean{showexercisesolutions}{false}
 \graphicspath{{likelihood/lecture/}{likelihood/lecture/figures/}}
 \lstset{inputpath=likelihood/code}
 \include{likelihood/lecture/likelihood}