9514 1404 393
Answer:
(x, y) = (3, 12)
Step-by-step explanation:
Using the given variable definitions, we can write the equations ...
y = x + 9
2(x +y) = 30
__
Solving the second equation for y, we have ...
y = 15 -x
Substituting this into the first equation gives ...
15 -x = x +9
6 = 2x . . . . . . . . . add x-9
3 = x . . . . . . . . . . divide by 2
y = 3+9 = 12 . . . . substitute into the first equation
The numbers are (x, y) = (3, 12).
Given:
μ = 2 min, population mean
σ = 0.5 min, population standard deviation
We want to find P(x>3).
Calculate the z-score
z= (x-μ)/σ = (3-2)/0.5 = 2
From standard tables, obtain
P(x ≤ 3) = P(z ≤ 2) = 0.9772
Therefore
P(x > 3) = P(z > 2) = 1 - 0.9772 = 0.0228
Answer: 0.02275
If x is how long your friend swims and y is how long you swim, the answer would be x + 15 = y
