Question 61

The average age of 3 girls is 24 years and their ages are in the proportion of 7 : 8 : 9. What is the age of the eldest girl?

Solution

The average age of 3 girls is 24 years and their ages are in the proportion of 7 : 8 : 9.

Let's assume the ages of 3 girls are 7y, 8y and 9y.

$$\frac{7y+8y+9y}{3}\ =\ 24$$

$$24y\ =\ 72$$

y = 3

Age of the eldest girl = 9y

= $$9\times3$$

= 27 years

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