Chemical coagulants can be added to muddy river water to clump suspended solids together so they can be filtered out. In an investigation, different masses of Coagulant X were added to 1000 cm³ samples of river water. The experiment was repeated with Coagulant Y.

The percentages of suspended solids removed are shown in the table below.

Table 1: Effectiveness of Coagulants X and Y

A student concluded:

"The most effective way to purify 1000 cm³ of this river water is to add 60 mg of Coagulant Y."

Use the data in Table 1 to evaluate the student's conclusion.