Average Practice Test 6

Question : 9 of 40

Marks: +1, -0

The average age of 9 friends is 21 years. The average of the first two friends is

23 /2

years and that of the next three friends is

25 /3

years. If the age of the sixth friend be less than the age of the seventh and eighth friends by 5 and 8 respectively, then what is the age of the eighth friend?

51 years
50 years
49 years
$50 2/3$ years
55 years

Validate

Solution:

Let the age of the 8th friend be x years.
Then, age of the 6th person = (x - 8) years
Age of the 7th person = (x - 8) + 5 = (x - 3) years

So,

(2×23/2)+(3×25/3)+(x-8)+(x-3)+x=9×21

23 + 25 + x - 8 + x - 3 + x = 189

3x = 189 - 37

3x = 152

x= 50 2/3

years

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