Answer:
40 mins
Step-by-step explanation:
33/60 = 0.55
22/0.55 = 40
First translate the English phrase "Four times the sum of a number and 15 is at least 120" into a mathematical inequality.
"Four times..." means we're multiplying something by 4.
"... the sum of a number and 15..." means we're adding an unknown and 15 and then multiplying the result by 4.
"... is at least 120" means when we substitute the unknown for a value, in order for that value to be in the solution set, it can only be less than or equal to 120.
So, the resulting inequality is 4(x + 15) ≤ 120.
Simplify the inequality.
4(x + 15) ≤ 120
4x + 60 ≤ 120 <-- Using the distributive property
4x ≤ 60 <-- Subtract both sides by 60
x ≤ 15 <-- Divide both sides by 4
Now that we have the inequality in a simplified form, we can easily see that in order to be in the solution set, the variable x can be no bigger than 15.
In interval notation it would look something like this:
[15, ∞)
In set builder notation it would look something like this:
{x | x ∈ R, x ≤ 15}
It is read as "the set of all x, such that x is a member of the real numbers and x is less than or equal to 15".
9514 1404 393
Answer:
Step-by-step explanation:
The Pythagorean theorem tells you that the area of the square with side 'a' is the difference of the areas of the other two squares.
a² = 7² -4²
a² = 49 -16 = 33
a = √33
Answer:
Plan II
Step-by-step explanation:
A certain county has 1,000 farms.
Corn is grown on 100 of these farms but on none of the others.
Since corn is grown on only 100 of these farms, the population of interest is the 100 farms on which corn is grown.
Therefore, a better method for estimating the total farm acreage of corn for the county is Plan II.
a) Identify the 100 corn-growing farms.
b) Sample 20 corn-growing farms at random.
c) Estimate the mean acreage of corn for corn-growing farms in a confidence interval.
d) Multiply both ends of the interval by 100 to get an interval estimate of the total.
