Make the given changes in the indicated examples of this section and then solve the resulting problems.

In Example 3, in the second line, change “4 more slides” to “3 more slides.”

Data from Example 3

A medical researcher finds that a given sample of an experimental drug can be divided into 4 more slides with 5 mg each than with 6 mg each. How many slides with 5 mg each can be made up?

We are asked to find the number of slides with 5 mg, and therefore we
let x = number of slides with 5mg
Because the sample may be divided into 4 more slides with 5 mg each than of 6 mg each, we know that
x − 4 = number of slides with 6mg
Because it is the same sample that is to be divided, the total mass of the drug on each set of slides is the same. This means

5x = 6(x − 4)

5x = 6x − 24

−x = −24 or x = 24

Therefore, the sample can be divided into 24 slides with 5 mg each, or 20 slides with 6 mg each. Since the total mass, 120 mg, is the same for each set of slides, the solution checks with the statement of the problem.