Good formula for turning star reviews into upvotes
My recommendation would be to explore some statistical approach to represent the reviews/rating pair as significance. For example, to translate the [# reviews, rating] into some test statistic type model, such as Student's t for starters. 

Considering your example numbers, some approaches can be:

1) 

&gt;&gt;&gt; 5/(1/sqrt(10))
15.811388300841896
&gt;&gt;&gt; 3/(1/sqrt(10))
9.4868329805051381
&gt;&gt;&gt; 
&gt;&gt;&gt; 
&gt;&gt;&gt; 4/(1/sqrt(60))
30.98386676965934
&gt;&gt;&gt; 5/(1/sqrt(10))
15.811388300841896


2) Or, diving deeper into stats,:

&gt;&gt;&gt; (5-3)/(sqrt(1/10+1/10))
4.4721359549995796
&gt;&gt;&gt; (4-5)/(sqrt(1/60+1/10))
-2.9277002188455996

(you will need to do some work on the alpha level to get at the significance in ex 2 above)


You can see how these work out for you; if too basic/too many inaccurate assumptions/some other filtering that you need more resolution in your model/etc., you can explore ways to better represent:


the sample standard deviation (assumed to be 1 in my examples above), or
the distribution (assumed Gaussian in examples above), or 
the appropriate statistical test (plow through Wikipedia), or 
etc


Point is you can continuously refine your model, depending how much resolution you need. Only you can make that call. Hope this helps!