There are two steps to this problem. The first step is to make an equation for the cost of each company. The cost of each one involves 2 variables. However, we can ignore the number of days since the question asks for per day.
CostA = 90 + .40(miles)
CostB = 30 + .70(miles)
We want to know when A is a better deal or when A costs less. That is when CostA < CostB. We can then substitute the right sides of our equations into the inequality. This will give:
90 + .40(miles) < 30 + .70(miles) This is where we will now begin to solve for the number of miles.
-30 -30 Subtract 30 from both sides.
60 + .4(miles) < .7(miles) Simplify
-.4(miles) -.4(miles) Subtract .4(miles) from both sides
60 < .3(miles) Simplify
/.3 /.3 Divide both sides by .3
200 < miles Simplify
So for A to cost less the number of miles must be greater than 200.
The number of buckets is directly proportional to the area and the thickness of the wall and inversely proportional to the amount of paint. Mathematically, we can write:
n = k · (a · t) / p
where k is the proportionality constant which we do not know.
We can calculate k with the given data: 5 2-gallon buckets, area of 100 square feet and thickness 3 inches:
k = (n · p) / (<span>a · t)
= (5 </span>· 2) / (100 · 3) = 0.0333
Now that we know the constant, we can calculate the area that can be painted with 8 2-gallon buckets if the thickness is 6 inches:
a = (n · p) / (k<span> · t)
= (8 </span>· 2) / (0.0333 · 6)
= 80 ft²
Please, note that we made sure to have the exact same units of measurements than the previous case.
Therefore, the correct answer is an area of 80 ft².
4 liters is slightly bigger
<span>In the question "Based on the data in the two-way table, what is the probability that a person weighs 120 pounds, given that he or she consumes 2,000 to 2,500 calories per day?"
The probability of an event, say A given another event, say B is given by n(A and B) / n(B).
Thus the probability that a person weighs 120 pounds, given that he or she consumes 2,000 to 2,500 calories per day is given by number of persons that weigh 120 pounds and consume 2,000 to 2,500 calories per day / number of persons that consume 2,000 to 2,500 calories per day.
From the table, the number of persons that weigh 120 pounds and consume 2,000 to 2,500 calories per day is 10 while the number of persons that consume 2,000 to 2,500 calories per day is 110.
Therefore, the required probability is 10 / 110 = 1 / 11</span>
