Answer:
50 and C
Step-by-step explanation:
Remark.
The geometric mean is the middle number between two numbers that are 2 places apart. It's easier just to make up an example to show what the mean is
4 8 16
8 is the geometric mean of 4 and 16. The first term (4) is multiplied by 2. The third term is derived from 8 (the mean) multiplied by 2
So to solve this problem you need to find what a is multiplied to get get the mean, and multiplied again by the same thing you did before to go from the mean to the third term.
Solution
12 / mean = mean / a Cross multiply
mean^2 = 12*a
But the mean is given as 10sqrt(6)
12a = 100 * 6
12a = 600
a = 50
20 / mean = mean /a
mean^2 = 20 a
mean = 10 sqrt (10)
100 * 10 = 20*a
a = 1000 / 20
a = 50
