The average of five numbers is 57.8.The average of the first and the second numbers is 77.5 and the average of the fourth and fifth numbers is 46.What is the third number ?
Let the numbers be a,b,c,d and e.
Now $$\frac{a+b+c+d+e}{5}$$=57.8*5
a+b+c+d+e=292
Now, $$\frac{a+b}{2}$$=77.5, a+b=155
Also, $$\frac{d+e}{2}$$=46, d+e=92.
Now, c=292-(a+b)-(d+e)=292-92-155=42.
Hence, the correct option is C.
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