I write an engineering text and I construct the sentence:
In practical applications two types of approaches can be found.
After the sentence, I describe the first "deterministic" and the second "stochastic" approach. My supervisor changed it to ..."types of approach" as singular form.
A few lines after I summarise and I say "...both approaches are similar in terms..." and my supervisor did not change this one, which even confuse me more.
As far as I understand, the approach is use as a method so I should use "types of methods". I try to google similar sentences with singular form but only found something like types of approach to somebody in sense that there is one approach only but the person can be approached in a different manner, but when is already approached, the story finish. (I hope it make sens)
My question is why in my case approach is changed to a singular form if I have the different methods?
Is there any rule or explanation which can be used in future similar context?