Answer:
33
Step-by-step explanation:
4,14,24,34,40,41,42,43,44,45,46,47,48,49,54,64,74,84,94,
104,114,124,134,140,141,142,143,144,145,146,147,148,149
68% of plans cost between $62.16 and $86.52.
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean: 74.34
Standard deviation: 12.18
Bell-shaped is the same as normally distributed.
Estimate the number of plans that cost between $62.16 and $86.52.
62.16 is one standard deviation below the mean.
86.52 is one standard deviation above the mean.
By the Empirical rule, 68% of the measures are within 1 standard deviation of the mean.
So
∠CAB = 33 {alternate interior angles}
5x = 33 + 2x { exterior angle equals sum of opposite interior angles}
5x - 2x = 33
3x = 33
x = 33/3
x = 11
∠B = 2x = 2* 11 = 22
∠ECB = 5x = 5*11 = 55
