Answer:
A week is 7 days so if she spends 3 hours a day that 21 hours during a whole week. Since we are trying to find 4 weeks we multiply by 4
21*4=84
Hope This Helps!!!
Answer:
the students should not have multiplied each expression by 2
Answer:
0.9973 is the percentage of American men whose height is between 61 and 79 inches.
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 70 inches
Standard Deviation, σ = 3 inches
We are given that the distribution of heights of American men is a bell shaped distribution that is a normal distribution.
Formula:

P(height is between 61 and 79 inches)

0.9973 is the percentage of American men whose height is between 61 and 79 inches.
F(x^2) = x^2 - 3
5f(x^2) = 5x^2 - 15 = 2x - 8
Placing all the terms on the left side, we get:
5x^2 - 2x - 7 = 0 which factorises to
(5x - 7)(x + 1) = 0
So, x = 7/5 or x = -1
But x is non-negative, so x = 7/5 = 1 2/5
C is the answer.