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Answer: 0.0793
Step-by-step explanation:
Let the IQ of the educated adults be X then;
Assume X follows a normal distribution with mean 118 and standard deviation of 20.
This is a sampling question with sample size, n =200
To find the probability that the sample mean IQ is greater than 120:
P(X > 120) = 1 - P(X < 120)
Standardize the mean IQ using the sampling formula : Z = (X - μ) / σ/sqrt n
Where; X = sample mean IQ; μ =population mean IQ; σ = population standard deviation and n = sample size
Therefore, P(X>120) = 1 - P(Z < (120 - 118)/20/sqrt 200)
= 1 - P(Z< 1.41)
The P(Z<1.41) can then be obtained from the Z tables and the value is 0.9207
Thus; P(X< 120) = 1 - 0.9207
= 0.0793
Let b be the number of blue beads and g the number of green beads that Giovanni can use for a belt.
He's supposed to use a total of between 70 and 74 beads, so
70 ≤ b + g ≤ 74
The ratio of green beads to blue beads is g/b, and this ratio has to be between 1.4 and 1.6, so
1.4 ≤ g/b ≤ 1.6
For completeness, Giovanni must use at least one of either bead color, so it sort of goes without saying that this system must also include the conditions
b ≥ 0
g ≥ 0
(These conditions "go without saying" because they are implied by the others. g/b is a positive number, so either both b and g are positive, or they're both negative. But they must both be positive, because otherwise b + g would be negative. I would argue for including them, though.)
0.4x 0.4x 0.4 = (0.4)^3
Exponential form = (0.4)^3