There is 31 students in a class. From mathematics was'nt worse mark than 2. Average mark in mathematics was 2.

How many students have mark 1 and how many mark 2?


n(1) =  0
n(2) =  31


Solution in text n(2) =

(1*a+2*b)/31 = 2

a+2b = 62
a+b = 31

a = 0
b = 31

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