In the following sentence which way would be correct?
Один/одна из тех людей, которые никогда не откажут в помощи - это наш врач.
The singular of люди is человек which is male. But what if the aforementioned doctor is a female?
In the following sentence which way would be correct?
Один/одна из тех людей, которые никогда не откажут в помощи - это наш врач.
The singular of люди is человек which is male. But what if the aforementioned doctor is a female?
In a sentence as you wrote it, when you refer to some generic doctor, you will use один (masculine) version in a sentence like this:
Один из тех людей, которые никогда не откажут в помощи - это наш врач.
The main reason for it is not that the singular of люди is человек (which is masculine), but that врач is masculine (as a word, not a person). This is why you use наш with it. You could say
Одна из тех людей, которые никогда не откажут в помощи - это наша врач.
In this case you are referring to a specific doctor - and in that case using одна would be grammatically correct: if you are talking about a specific female doctor in a specific group of people. Another example would be
Одна из этих людей - наша врач.
However in a general conversation you would use word один.
Well, you use "врач", and it's male. So, You should use "один" here:
Один из тех людей, которые никогда не откажут в помощи - это наш врач.
But if noun whould be female, you should use female form. For example:
Одна их тех людей, которые никогда не откажут в помощи -- это наша мать.
You should use 'Один из тех людей, которые никогда не откажут в помощи - это наш врач,' because врач means a male doctor so you should use Один.