Quantities that are proportional to 26/13 are any other fractions that can reduce to positive 2.
26/13 = 26 ÷ 13 = 2
10/5 = 10 ÷ 5 = 2
200/100 = 200 ÷ 100 = 2
Answer:
6.5 hours
Step-by-step explanation:
First try to find the rate he can paint per hour
375 ÷ 3 = 125 ft^2 per hour
Then try to find how long it should take it for him to paint 812.5 sq ft
812.5 ÷ 125 = 6.5 hours
I'm guessing you intended to say has mean and standard deviation , and has means and standard deviation .
If , then has mean
and variance
Given that and , we have
Then
and are independent, so , and
so that the variance, and hence standard deviation, are
# # #
Alternatively, if you've already learned about the variance of linear combinations of random variables, that is
then the variance of is simply the sum of the variances of and , , and so the standard deviation is again .
-1 - v - 3v < 15
-1 - 4v < 15
-4v < 16
v > -4