School - two grades

There are 420 pupils in the school. Two hundred fifty-two pupils go to the 1st level. Write as a fraction what part of the pupils goes to the 1st grade and what part to the 2nd grade. Reduce both fractions to proper form.

Final Answer:

a =  3/5
b =  2/5

Step-by-step explanation:

$$\begin{gathered} n=420 \\ p=252 \\ a=\frac{p}{n}=\frac{252}{420}=\frac{3}{5}=0.6 \end{gathered}$$

$$\begin{gathered} d=n-p=420-252=168 \\ b=\frac{d}{n}=\frac{168}{420}=\frac{2}{5}=0.4 \end{gathered}$$

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