Five years ago, the average age of four girls, was 7 years. A new girl is included then the average present age becomes 13 years. The present age of the new girl is:

14 years 19 years 16 years 17 years

17 years

Sum of present age of 5 girls = 4 × 7 + 4 × 5 = 48 years New girls is added .Now sum of age of 5 girls = 5 × 13 = 65 years Age of new girl = 65 - 48 = 17 years