Yes 678.05 is greater than 67.805 (because obviously 678 is greater than 67 right? ^ - ^)
Ok so to find the ratio just do 12/16 = 3/4. that's your common ratio.
The formula for sum of infinite :
a / (1 - r)
a is the first term and r is the ratio
which is
16 / (1 - (3/4))
which is
16 / (1/4)
16 * 4
which is 64
Answer:
1) 70 for both of them
2) Plot A's range is 100-50 = 50, Plot B's range is 100 - 40 = 60 so Plot A has the lesser range
3) Plot B's IQR is 85 - 60 = 25, Plot A's IQR is 80 - 65 = 15 so Plot B has the greater IQR
4) A: 80, B: 85
5) A: 65, B: 60
6) 50
7) 100
8) Plot B, see #2 for work
9) 50% - 50% of data is always between Q1 and Q3
10) 25%
11) 25%

we can rewrite it as

we can see that 1/4 is in multiple in both terms
so, we can factor it out
so, we get
..............Answer
If they sold 89 calendars over 4 weeks, the 'equation' would look like (x = average calendars sold over 4 weeks):

If you solve it, you get:

Which is equal to
22.25. Hope this helps!