Marble color distribution

I have 100 marbles. One-quarter of them are white, and 3 fifths of the rest are blue. 1 third of those that are neither blue nor white are red, and the rest are green. How many marbles do I have?

Final Answer:

a =  25
b =  45
c =  10
d =  20

Step-by-step explanation:

$$\begin{gathered} n=100 \\ a=n/4=100/4=25 \end{gathered}$$

$$\begin{gathered} z=n-a=100-25=75 \\ b=\frac{3}{5}\cdot z=\frac{3}{5}\cdot 75=\frac{3\cdot 75}{5}=\frac{225}{5}=45 \end{gathered}$$

$c=(n-a-b)/3=(100-25-45)/3=10$

$d=n-(a+b+c)=100-(25+45+10)=20$

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