Question

if the manufactures recipe says to use 15 g of agar per 1 l of water, how much agar should i use to make 400 ml of the agar/water mixture?
12 g
6 g
6000 g
1000 g

Explanation:

Step1: Convert units

Since \(1L = 1000mL\), we can set up a proportion. Let \(x\) be the amount of agar needed for \(400mL\) of the mixture.

Step2: Set up proportion

The ratio of agar to water is \(\frac{15g}{1000mL}\). For \(400mL\) of water, the proportion is \(\frac{15g}{1000mL}=\frac{x}{400mL}\).
Cross - multiply: \(1000x = 15\times400\).

Step3: Solve for \(x\)

\(1000x=6000\), then \(x = \frac{6000}{1000}=6g\).

Answer:

6 g