Question

a nursery worker needs to make a solution of fertiliser. she mixes water with pesticide in the ratio of 10:4. if 800 ml of water is required how much pesticide will be needed?

Explanation:

Step1: Set up proportion

Let $x$ be the volume of pesticide. The ratio of water to pesticide is $10:4$, and we know the volume of water is 800 ml. So we have the proportion $\frac{10}{4}=\frac{800}{x}$.

Step2: Cross - multiply

$10x = 4\times800$.

Step3: Solve for $x$

$x=\frac{4\times800}{10}=320$.

Answer:

320 ml