one third of the students in class scored 90% or better on a test two fifths of the students scored 80%-89% on the test the rest of the students scored below 80% on the test what fraction of te students scored below on the test

Answer 1

Let's denote the total number of students in the class as $x$.

According to the problem:

• One third of the students scored 90% or better: $\frac{1}{3}x$
• Two fifths of the students scored 80%-89%: $\frac{2}{5}x$

To find the fraction of students who scored below 80%, we first need to add the fractions of students who scored 90% or better and those who scored 80%-89%.

We need a common denominator to add these fractions. The least common multiple of 3 and 5 is 15. We can convert the fractions as follows:

• $\frac{1}{3}=\frac{5}{15}$
• $\frac{2}{5}=\frac{6}{15}$

Now, we can add these two fractions:

$$\frac{5}{15}+\frac{6}{15}=\frac{11}{15}$$

This means that $\frac{11}{15}$ of the students scored either 90% or better or 80%-89%. To find the fraction of students who scored below 80%, we subtract this result from 1:

$$1-\frac{11}{15}=\frac{15}{15}-\frac{11}{15}=\frac{4}{15}$$

Therefore, the fraction of students who scored below 80% on the test is $\frac{4}{15}$.