The average number of runs scored by Virat Kohli in four matches is 48...
Runs scored by Kohli in first 4 innings = 48*4 = 192
Average of 5 innings is 60, so total runs scored after 5 innings = 60*5 = 300
Hence runs scored by Kohli in fifth inning = 300 – 192 = 108
It is given that in 6th innings he scores 12 runs more than this, so he must score 120 in the sixth inning. Hence total runs scored in 6 innings = 300+120 = 420
Now average of last five innings is 78, so runs scored in last innings = 390
Hence runs scored in first inning = 420 – 390 = 30.
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The average number of runs scored by Virat Kohli in four matches is 48...
Given:
- Average runs scored by Virat Kohli in four matches = 48
- Average runs scored by Virat Kohli in five matches = 60
- Average of last five innings = 78
- Kohli does not remain not out in any of the innings
To Find: Runs scored by Kohli in his first innings
Solution:
Let the runs scored by Kohli in his first, second, third, fourth, fifth and sixth innings be x, y, z, w, a and b respectively.
Average runs scored by Kohli in four matches = 48
Therefore, total runs scored by Kohli in four matches = 48 * 4 = 192
Also, total runs scored by Kohli in first four innings = x + y + z + w
Average runs scored by Kohli in five matches = 60
Therefore, total runs scored by Kohli in five matches = 60 * 5 = 300
Also, total runs scored by Kohli in first five innings = x + y + z + w + a
We can write an equation from the above information:
x + y + z + w = 192
x + y + z + w + a = 300
Kohli scores 12 runs more in his sixth innings than his fifth innings
Therefore, runs scored by Kohli in his sixth innings = a + 12
Average of last five innings = 78
Therefore, total runs scored by Kohli in last five innings = 78 * 5 = 390
Also, total runs scored by Kohli in his first six innings = x + y + z + w + a + (a + 12) = x + y + z + w + 2a + 12
We can write another equation from the above information:
x + y + z + w + 2a + 12 = 390
Solving the above two equations, we get:
x + y + z + w = 192
x + y + z + w + a = 300
x + y + z + w + 2a + 12 = 390
Subtracting the first equation from the second equation, we get:
a = 108
Substituting the value of a in the second equation, we get:
x + y + z + w = 192
x + y + z + w + 108 = 300
x + y + z + w = 192
Therefore, runs scored by Kohli in his first innings = (x) = (192 - (y + z + w))
We don't have enough information to find the exact value of x, y, z and w. However, we can find the minimum value of x by assuming that y, z and w are all equal to 0 (i.e. Kohli did not score any runs in his second, third and fourth innings).
Therefore, runs scored by Kohli in his first innings = (x) = (192 - (0 + 0 + 0)) = 192
Hence, the correct option is (a) 30.
The average number of runs scored by Virat Kohli in four matches is 48...
Runs scored by Kohli in first 4 innings = 48*4 = 192
Average of 5 innings is 60, so total runs scored after 5 innings = 60*5 = 300
Hence runs scored by Kohli in fifth inning = 300 – 192 = 108
It is given that in 6th innings he scores 12 runs more than this, so he must score 120 in the sixth inning. Hence total runs scored in 6 innings = 300+120 = 420
Now average of last five innings is 78, so runs scored in last innings = 390
Hence runs scored in first inning = 420 – 390 = 30.