Question 1124566
total=average*n, by rewriting the definition of an average
total=17 (1/3), for 4 months is 1/3 of a year *3=52
two have a total of 17 (1/4)*2=34 (1/2)
The third girl is 52-34 (1/2)=17 (1/2) or 17 years 6 months