Question 68

The average of 11 results is 50. The average of the first 6 results is 49 and that of the last 6 results is 52. What is the $$6^{th}$$ result?

Solution

Let say, 11 results are R1,R2,R3,.....,R11.

so,$$(R1+R2+....+R11)=50×11=550$$.....(1)

Sum of first six results would be 49×6=294.

And Sum of last six results would be 52×6=312.

So,R1+R2+....+R6=294........(2)

And R6+R7+....+R11=312.......(3)

if we add (2)&(3):

R1+R2+.....+2(R6)+.....+R10+R11=312+294=606..........(4)

Equation(4)-(1) :

R6=56.

C is correct choice.

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