The average age of 26 girls in a class decreases by 6 months when a new girl takes the place of a 20-year-old girl. What is the age of the new girl?
1
7 years
2
8 years
3
9 years
4
10 years
5
11 years
The average age of 26 girls in a class decreases by 6 months when a new girl takes the place of a 20-year-old girl. What is the age of the new girl?