The average age of 25 girls in a class is 11.2 years and that of the remaining 15 girls is 10 years. Find the average age of all the girls in the class.
Answer & explanation
Correct answer: option 1
Sum of ages of all girls = 25x 11.2 + 15 x10 = 430
Avg. age = \(\frac{430}{40}\) = 10.75 years