The answer is 7x = 6(x + 15)

x - Jim's rate
y - Pete's rate
Jim completed half the floor in 7 hours: 7x = half of the floor
Pete completed the other half of the floor in 6 hours: 6y = half of the floor
So: 7x = 6y

Pete can lay 15 more tiles per hour than Jim: y = x + 15

7x = 6y
y = x + 15

Substitute the second equation into the first one:
7x = 6(x + 15)

6 0

3 years ago

Suppose the correlation between height and weight for adults is +0.40. What proportion (or percent) of the variability in weight

Schach [20]

Answer:

We are given the correlation between height and weight for adults is 0.40.

We need to find the proportion of the variability in weight that can be explained by the relationship with height.

We know that coefficient of determination or R-square measures the proportion or percent of variability in dependent variable that can be explained by the relationship with independent variable. There the coefficient of determination is given below:

$R^{2}=r^{2}=0.40^{2}=0.16$

Therefore, the 0.16 or 16% of the variability in weight can be explained by the relationship with height

7 0

3 years ago

What is the complete factorization of r2 - 6r - 9s2 + 9? A) (r - 3 + 3s)(r - 3 - 3s) B) (r + 3 + 3s)(r - 3 - 3s) C) (r - 3 + 3s)

nikitadnepr [17]

$r^2-6r-9s^2+9=r^2-6r+9-9s^2=r^2-2\cdot r\cdot3+3^2-9s^2\\\\\text{use}\ (a-b)^2=a^2-2ab+b^2\\\\=(r-3)^2-9s^2=(r-3)^2-(3s)^2\\\\\text{use}\ a^2-b^2=(a-b)(a+b)\\\\=(r-3-3s)(r-3+3s)\to A$

6 0

3 years ago