Answer
$219
Work Step by Step
In ascending order: 20, 46, 68, 70, 79, 89, 90, 95, 98, 101, 111, 112, 112, 113, 133, 143, 166, 174, 188, 212
The second quartile is equal to the median. Since we have 20 observations, the median is the mean between the 10th and the 11th observations in ascending order:
$Q_2=\frac{101+111}{2}=106$
The botton half of the data: 20, 46, 68, 70, 79, 89, 90, 95, 98, 101. $Q_1$ is the median of these values. Since there are 10 observations, the median is the mean between the fifth and the sixth observations in ascending order:
$Q_1=\frac{79+89}{2}=84$
The top half of the data: 111, 112, 112, 113, 133, 143, 166, 174, 188, 212. $Q_3$ is the median of these values. Since there are 10 observations, the median is the mean between the fifth and the sixth observations in ascending order:
$Q_3=\frac{133+143}{2}=138$
$IQR=Q_3-Q_1=138-84=54$
$Upper~fence=Q_3+1.5\times IQR=138+1.5\times54=219$
