Answer:
53
Step-by-step explanation:
To find the interquartile range (IQR), first find the median (middle value) of the lower and upper half of the data. These values are quartile 1 (Q1) and quartile 3 (Q3). The IQR is the difference between Q3 and Q1.
Since a(n)=-3(a(n-1)) the common ratio is -3, and a(1)=-3 so
a(n)=-3(-3^(n-1)) so the first four terms are:
-3, 9, -27, 81