Answer :
Alright, lets get started.
Total numbers of customers = 850
Number of men = 375
Number of women = total number of customer - number of men
Number of women = 850 - 375
Number of women = 475
Ratio of women to men customer = 475 / 375 (475 & 375 is divisble with 5)
Ratio of women to men customer = 95/75 (95 & 75 is again divisble with 5)
Ratio of women to men customer = 19 / 15
Hence the simplest form of women to men customer = 19:15 : Answer
Hope it will help :)