Answer:
64.75
Step-by-step explanation:
The total heights of men is m
so m/15 = 69.65 => m = 1044.75
The total heights of all students is s
so s/35 = 66.85 => s = 2339.75
so the total heights of women = 2339.75 - 1044.75 = 1295
The mean height of women = 1295/20 = 64.75