Um the 2nd one has a star
For a known standard deviation, the confidence interval for sample size = n is

where
x = average
n = sample size

= stad. deviation
z = contant that reflects confidence interval
Let a = x
Let b =

From the given information,
a - b = 0.432 (1)
a + b = 0.52 (2)
Add (1) and (2): 2a = 0.952 => a = 0.476
Subtract (2) from (1): -2b = -0.088 => b = 0.044
Therefore, the confidence interval may be written as
(0.476 - 0.044, 0.476 + 0.044), or as
(0.476

0.044)
Annual interest
50000 * (9.5 / 100)
4750
Interest for 12 months = 4750
Interest for 8 months
(4750/12) * 8
$ 3166.67
Simple, 7/12 is greater than 1/3 because 7/12=0.58333 and 1/3=0.333, 0.58333 is greater than 0.333. That is how I know that 7/12 is greater than 1/3. I know that 1/3 is less than 2/3 because 1/3=0.333 and 2/3=0.666, 0.333 is less than 0.666