Solution

Given:

• Average run scored by Steve in past ‘n’ matches= 65.
• In today’s match, he scored a century.
• New average after he hit the century is 70 runs.

To find:

• The value of n

.

Approach and Working:

Method-1

• \(\frac{Sum\ of\ run\ in\ n\ matches}{n}= 65\)

o Sum of runs in n matches= 65n

• \(\frac{Sum\ of\ runs\ in\ n\ matches+100}{n+1}= 70\)

o 65n+100= 70n+70
o 5n= 50
o n=6

Hence, the correct answer is option B.
Answer: B
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Equation is one way.
Another way is to think about the the impact 100 had on 65's which increased it to 70.
Since the new average is 70 , the excess score for the last match is 100-70 = 30.
We have 30 runs which we can distribute to the previous matches to bring it up to 70.
Since each score needs to be increased by 5 , we get 30/5 = 6