Answer:
b. 5
Step-by-step explanation:
In a stem and leaf plot, each observation is split into a stem (the first digit or digits) and a leaf (usually the last digit).
In this example, the entries in the 20s, 30s, and 40s are:
20, 20, 24, 25, 26, 35, 36, 43, 43
We omit 20, 20, 43, and 43 because they are not between 20 and 40.
That leaves the five observations
24, 25, 26, 35, 36
