Test Grades Distribution Students

No one got a grade worse than three. A third of the class got one, two-fifths two, and eight students had three. How many students had one or two?

Final Answer:

a =  10
b =  12

Step-by-step explanation:

$$\begin{gathered} n/3+2/5n+8=n \\ n/3+2/5\cdot n+8=n \\ 4n=120 \\ n=\frac{120}{4}=30 \\ n=30 \\ a=n/3=30/3=10 \end{gathered}$$

$b=\frac{2}{5}\cdot n=\frac{2}{5}\cdot 30=\frac{2\cdot 30}{5}=\frac{60}{5}=12$

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