Ex. 1. The average of nine numbers ...
Question

# Ex. 1. The average of nine numbers is 50. The aveias of the first five numbers is 54 and that of the last three number is 52. Then the sixth number is (1) 30 (3) 24 (2) 34 (4) 44 SSC CGL (Tier-I) 2013

11th - 12th Class
Maths
Solution
46
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Sol. (3) Let the sixth number be ( x ). Sum of first 5 numbers ( =5 times 54=270 ) Sum of last 3 numbers ( =3 times 52=156 ) Average of nine numbers ( =frac{270+156+x}{9}=50 ) ( Rightarrow 426+x=450 Rightarrow x=450-426=24 )