A class of 30 students has average marks 60. A new student joins and the average rises to 61. The new student scored:
A$61$
B$70$
C$80$
D$91$
Answer & Solution
Correct answer: D. $91$
New total = 61 × 31 = 1891. Old total = 60 × 30 = 1800. New student = 1891 − 1800 = 91.
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