A batsman scores 124 runs in his 21st innings and thereby increases his average by 4 runs. What is his average after 21 innings?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 44
The total runs equal the average multiplied by the number of innings. The total after 21 innings is the old total plus the 124 runs of the 21st innings.
Let the average for 20 innings be \(a\); total runs \(=20a\)
After the 21st innings the average is \(a+4\); total runs \(=21(a+4)\)
\(20a+124=21a+84\)
\(a=124-84=40\)
New average \(=40+4=44\)
His average after 21 innings is 44 runs. (40 is the average before the 21st innings, Option (2).)