Classs mean

Class size is 30 students, math was not worse than sign 2. Determine the number of pupils who were sign 1 if the class had a 1.4 sign average.

Correct answer:

a =  18

Step-by-step explanation:

a+b= 30
a+2b = 1.4 •30

a+b= 30
a+2•b = 1.4 •30

a+b = 30
a+2b = 42

a = 18
b = 12

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