Question

which of the following sets of dilutions could be combined to get to a total * 1 point dilution of 1:125
1:5 and 1:10
1:5 and 1:25
1:10 and 1:25
1:12 and 1:5

Explanation:

Step1: Recall dilution - combination rule

When combining dilutions, the total dilution is the product of the individual dilutions.

Step2: Calculate product for each option

For 1:5 and 1:10, the product is $\frac{1}{5}\times\frac{1}{10}=\frac{1}{50}$.
For 1:5 and 1:25, the product is $\frac{1}{5}\times\frac{1}{25}=\frac{1}{125}$.
For 1:10 and 1:25, the product is $\frac{1}{10}\times\frac{1}{25}=\frac{1}{250}$.
For 1:12 and 1:5, the product is $\frac{1}{12}\times\frac{1}{5}=\frac{1}{60}$.

Answer:

1:5 and 1:25