Question
The average marks obtained by a student in a certain
number of tests is 36. His average increases by 2 when he scores 90 in his next test. Find the total marks obtained by him before he scored 90.Solution
Let the number of tests taken by the student before he scores 90 be 'P'.
Marks scored before = 36P
(36P + 90) / (P + 1) = 38
=> 36P + 90 = 38P + 38
=> 2P = 52 => P = 26
Total marks before = 36 × 26 = 936
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