Answer:
20
Step-by-step explanation:
→ First find the value of x and y
x + y = 5
x - y = 4
→ Add the equations to cancel out the y's
2x = 9
→ Divide both sides by 2 to find the value of x
x = 4.5
→ Substitute x = 4.5 back into x - y = 4 to find the value of y
4.5 - y = 4
→ Minus 4.5 from both sides to isolate -y
-y = -0.5
→ Multiply everything by -1
y = 0.5
→ Substitute x = 4.5 and y = 0.5 into x² - y²
4.5² - 0.5² = 20.25 - 0.25 = 20
Answer:
I think it is 50 tell me if it is right
Answer: -25
Step-by-step explanation:
Answer:
0.8185 or 81.85%
Step-by-step explanation:
The mean length (μ) of an adult foot is 11 and the standard deviation (σ) is 1.5.
The z score is a measure in statistic used to determine the amount of standard deviation by which the raw score (x) is above or below the mean. If the raw score is above the mean, the z score is positive and if the raw score is below the mean the z sore is negative. It is given by:

To calculate the probability that a randomly selected male will have a foot length between 8 and 12.5 inches, we first calculate the z score for 8 inches and then for 12.5 inches.
For 8 inches:

For 12.5 inches:

From the normal distribution table, The probability that a randomly selected male will have a foot length between 8 and 12.5 inches = P(8 < x < 12.5) = P(-2 < z < 1) = P(z < 1) - P(z < -2) = 0.8413 - 0.0228 = 0.8185 = 81.85%