Comprehension

The batting average (BA) of a Test batsman is computed from runs scored and innings played — completed innings and incomplete innings (not out) in the following manner:

\[ r_1 = \text{Number of runs scored in completed innings} \] \[ n_1 = \text{Number of completed innings} \] \[ r_2 = \text{Number of runs scored in incomplete innings} \] \[ n_2 = \text{Number of incomplete innings} \]

\[ BA = \frac{r_1 + r_2}{n_1} \]

To better assess a batsman’s accomplishments, the ICC is considering two other measures MBA1 and MBA2, defined as follows:

\[ MBA_1 = \frac{r_1}{n_1} + \frac{n_2}{n_1} \max \left( 0, \left( \frac{r_2}{n_2} - \frac{r_1}{n_1} \right) \right) \]

\[ MBA_2 = \frac{r_1 + r_2}{n_1 + n_2} \]

Question: 1

Based on the above information which of the following is true?

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Write \(A_1=r_1/n_1\) and \(A_2=r_2/n_2\) and compare the three measures in terms of these averages; test a numerical example against each option.
Updated On: Nov 4, 2026
  • \(MBA_1 \le BA \le MBA_2\)
  • None of these
  • \(MBA_2 \le BA \le MBA_1\)
  • \(BA \le MBA_2 \le MBA_1\)
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The Correct Option is B

Solution and Explanation

Step 1: Rewrite the measures.
Let \(A_1=\frac{r_1}{n_1}\) and \(A_2=\frac{r_2}{n_2}\) (the average in completed and incomplete innings). Then
\[BA=A_1+\tfrac{n_2}{n_1}A_2,\qquad MBA_1=A_1+\tfrac{n_2}{n_1}\max(0,A_2-A_1),\qquad MBA_2=\frac{n_1A_1+n_2A_2}{n_1+n_2}.\]Step 2: Compare \(MBA_1\) with \(BA\).
\(BA-MBA_1=\frac{n_2}{n_1}\left[A_2-\max(0,A_2-A_1)\right]=\frac{n_2}{n_1}\min(A_1,A_2)\ge 0\). So \(MBA_1\le BA\).

Step 3: Compare \(MBA_2\) with \(MBA_1\).
\(MBA_2=A_1+\frac{n_2}{n_1+n_2}(A_2-A_1)\).
  • If \(A_2\le A_1\): \(MBA_1=A_1\ge MBA_2\).
  • If \(A_2>A_1\): \(MBA_1-MBA_2=(A_2-A_1)\,n_2\left(\frac1{n_1}-\frac1{n_1+n_2}\right)\ge 0\).
So in every case \(MBA_2\le MBA_1\le BA\).

Step 4: Test the options with an example.
Take \(r_1=100,\ n_1=2,\ r_2=100,\ n_2=1\): \(BA=100\), \(MBA_1=50+\frac12\cdot 50=75\), \(MBA_2=\frac{200}{3}\approx 66.7\).
  • (1) \(75\le 100\le 66.7\): false.
  • (4) \(100\le 66.7\le 75\): false.
  • (3) \(66.7\le 100\le 75\): false.
The correct relation is \(MBA_2\le MBA_1\le BA\), which is none of (1)-(3).

Final Answer:
The correct option is (2): None of these.
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Question: 2

An experienced cricketer with no incomplete innings has BA of 50. The next time he bats, the innings is incomplete and he scores 45 runs. It can be inferred that

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Before the innings \(n_2=0\), so all three measures equal 50. Recompute each measure after adding one incomplete innings of 45 runs.
Updated On: Nov 4, 2026
  • \(BA\) and \(MBA_1\) will both increase
  • \(BA\) will increase and not enough data is available to assess change in \(MBA_1\) and \(MBA_2\)
  • \(BA\) will increase and \(MBA_2\) will decrease
  • None of these
Show Solution
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The Correct Option is C

Solution and Explanation

Step 1: Before the innings.
No incomplete innings, so \(n_2=0\), \(r_2=0\), and \(r_1=50\,n_1\). Then \(BA=\frac{r_1}{n_1}=50\), \(MBA_1=\frac{r_1}{n_1}=50\) and \(MBA_2=\frac{r_1}{n_1}=50\).

Step 2: After the incomplete innings (\(r_2=45,\ n_2=1\)).
  • \(BA=\frac{50n_1+45}{n_1}=50+\frac{45}{n_1}>50\). BA increases (the denominator \(n_1\) does not change since the innings is incomplete).
  • \(MBA_1=50+\frac{1}{n_1}\max(0,\,45-50)=50+0=50\). MBA\(_1\) is unchanged.
  • \(MBA_2=\frac{50n_1+45}{n_1+1}=50-\frac{5}{n_1+1}<50\). MBA\(_2\) decreases.
Step 3: Match with the options.
(1) is false because \(MBA_1\) does not increase. (2) is false because the data suffices (the result holds for every \(n_1\)). (3) states exactly what we found: BA increases and \(MBA_2\) decreases.

Final Answer:
The correct option is (3): BA will increase and MBA\(_2\) will decrease.
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