Let the unknown amount be 'x' grams.
According to the question,
x of 8% solution should be used to make 100g of a 3% solution.
Let us find x of 8%
[tex] =x \times 8\% [/tex]
[tex] =x \times \frac{8}{100} [/tex]
=[tex] =\frac{8x}{100} [/tex] (Equation 1)
Now, we will find 100g of a 3%
[tex] = 100g \times 3\% [/tex]
[tex] = 100g \times \frac{3}{100} [/tex]
[tex] = 3 [/tex] g (Equation 2)
Now, equating equations 1 and 2,
[tex] \frac{8x}{100}=3 g [/tex]
[tex] 8x=300 g [/tex]
[tex] x=\frac{300}{8} g [/tex]
x = 37.5 grams
