Answer:
a) 9
b) 10
c) 8
Step-by-step explanation:
We are given the following in he question:
Mean of sample A = 6
Mean of sample B = 12
Formula:


a) original samples have n = 4 scores

b) first sample has n = 3 and the second sample has n = 6

c) first sample has n = 6 and the second sample has n = 3

A. 12 mm
The Pythagorean Theorem states that a^2 + b^2 = c^2 with a and b being lengths of legs and c being the length of a hypotenuse. So we can use our givens to solve for the remaining leg.
9^2 + b^2 = 15^2
81 + b^2 = 225
b^2 = 144
b = 12
If x is the distance the base of the ladder is from the wall, and y is the distance to top of the ladder is up the wall, then the Pythagorean theorem tells you
... x² + y² = 10²
Differentiating with respect to time, we have
... 2x·dx/dt + 2y·dy/dt = 0
... dy/dt = (-x/y)·dx/dt
We are given x = 6 ft and dx/dt = 3 ft/s. Using the first equation, we can find y as
... y = √(10² -6²) = 8
Then
... dy/dt =(-6/8)·(3 ft/s)
... dy/dt = -2.25 ft/s
The top of the ladder is sliding down the wall at -2.25 ft/s.
Word form: eighty-six million fifty-one thousand four hundred seventy-two