Physics doubt

Question

250 ml of milk having temperature 80 degree Celsius is mixed with 100 ml of water which is kept at 40 degree celsius, what will be the temperature of the mixture?

a) 90 degree celsius

b) 120 degree celsius

c) less than 40 degree celsius

d) more than 40 degree celsius and less than 80 degree celsius
 

Plz explain this question

Answer 1

=(80 degree+40 degree) /2

=120 degree/2

=60 degree

So option D is correct