First, find how much he paid by tire.
To do so, divide what he paid by how many tires he bought like this :
240$ / 12 = 20$ per tire

Then, calculate how much he sells each tire.
To do so, start by calculating how much he paid for 3 tires:
20$ x 3 = 60$

This is the price he sells 2 tires for, therefore :
60$ / 2 = 30$
he sells his tires 30$ each.

Finally, you have to calculate the profit he made by selling 12.
We already know how much it cost, so you need to find how much money he gets selling them :
12 tires x 30$ = 360$

To find the profit, take off the amount he paid from the amount he made :
360$ - 240$ = 120$

There you go!

3 0

2 years ago

Suppose the number of gallons of gasoline per day used by a car is normally distributed with a mean of 2.2 gallons and a standar

const2013 [10]

The difference in gallons per day used is 3.6.

The formula to calculate a z-score is:
$z=\frac{X-\mu}{\sigma}$ ,

where X is the value used to calculate the score, μ is the mean and σ is the standard deviation. We have the z-scores so we must work backward:

$3=\frac{X-2.2}{1.2}\text{ and }0=\frac{X-2.2}{1.2}$

For both equations, we will cancel the 1.2 by multiplying both sides:
$3\times1.2=(\frac{X-2.2}{1.2})\times1.2\text{ and }0\times1.2=(\frac{X-2.2}{1.2})\times1.2
\\
\\3.6=X-2.2\text{ and }0=X-2.2$

Now we will cancel 2.2 from both equations by adding it to both sides:

3.6+2.2=X-2.2+2.2 and 0+2.2=X-2.2+2.2
5.8=X and 2.2=X

The difference in gas used per day would be given by
5.8-2.2 = 3.6.

5 0

2 years ago