The average marks obtained by Raghav in 12 tests is 24. Zubeida has maintained an average of 23 so far but has taken only 9 of the tests. If each test is out of 30, at least how much must Zubeida score in any one of the remaining three tests to still have a chance to match Raghav’s performance?

Number of Tests by raghav = 12

Average in test by Raghav = 24

Total Score by Raghav = 24 * 12 = 288

Number of Tests by Zubeida = 9

Average = 23

Total score obtained by zubeida = 23 * 9 = 207

Numbers required to meet Raghav Performance = 288 - 207 = 81

Test remaining = 3

Average Score to be obtained in All remaining test = 81/3 = 27

Zubaida can score maximum 30 + 30 = 60 in two tests

So in remaining third test she can score 81 - 60 = 21