Consider the Relative Frequency Distribution Given Below There Were 60 Numbers in the Data Set

Multiple Choice

Consider the relative frequency distribution given below:
$$\begin{array} { l c } \text { Class Interval } & \text { Relative Frequency } \\\text { 20-under } 40 & 0.2 \\40 \text {-under } 60 & 0.3 \\60 \text {-under } 80 & 0.4 \\\text { 80-under } 100 & 0.1\end{array}$$
There were 60 numbers in the data set.How many numbers were in the interval 40-under 60?

A) 30
B) 50
C) 18
D) 12
E) 15