My daughter has a math question that says 2 kids looked at a chart and one said purple was 1/4...the other one said 1/10...teacher says both are...

There might be a different type of answer depending on the wording of the question and the context, but assuming the question says each girl's answer is correct, here is a possible scenario:

Imagine a chart of area 40 square units. Within the chart is an area with various colors, including purple, of area 16 square units. Suppose the purple area is 4 square units.

Then the purple area is 1/4 of the colored section of the chart. But the purple area is also 1/10 the area of the entire chart.

When dealing with fractions, it is important to identify the "whole" from which the "parts" are taken. For instance 1/4 of a foot is also 1/12 of a yard. For the scenario I used, the "whole" could be the entire area of the chart or just the colored section.