Answer:
A) 4
B) 9
C) 12
Step-by-step explanation:
X = the number of minutes the phone is used
<u>Plan A:</u>
40¢ per minute ($0.40)
no other costs
<em>Cost for 1 month = 0.4 x</em>
<u>Plan B:</u>
$30 a month, even if you don't use the phone at all
100 free minutes
then 50¢ per minute ($0.50)
Cost for 1 month:
If 'x' is less than 100: <em>Cost = 30</em>
<span>
If 'x' is greater than 100</span>:
Cost = 30 + 0.5(x - 100) (Because the first 100 minutes are free, and
you only pay for minutes past 100. There are [x-100] of those.)
Eliminate parentheses: Cost = 30 + 0.5x - 50
Combine like terms: <em> Cost = 0.5x - 20</em>
Which plan costs more ? It depends on how many minutes you use in a month.
If you use a small number of minutes, Plan A costs you more.
If you use a huge number of minutes, Plan B costs you more.
Where is the crossover point ? It's the number of minutes in one month
where the costs of both plans are equal.
<u>If you use the phone for less than 100 minutes a month,</u>
(where the cost of Plan B starts increasing with each minute):
0.4x = 30
Divide each side by 0.4: <em>x = 75</em>
Less than 75 minutes per month, Plan A costs less.
Past 75 minutes a month, Plan A costs more than $30, so Plan B costs less,
until Plan B starts charging for extra minutes.
<u>If you use the phone for more than 100 minutes a month: </u>
0.4 x = 0.5 x - 20
Add 20 to each side: 0.4 x + 20 = 0.5 x
Subtract 0.4x from each side: 20 = 0.1 x
Multiply each side by 10: <em> 200 = x</em>
There it is.
Now we can combine the results:
-- Less than 75 minutes in a month: Plan A costs less.
-- Between 75-200 minutes in a month: Plan B costs less.
-- More than 200 minutes a month: Plan A costs less again.
Complicated ? Absolutely ! That's why citizens' consumer groups are after
these companies, to try to get them to make their plans more understandable
to regular people. I know from personal experience that even a lot of the
salesmen in the phone stores could not figure this out and give you sound advice.
Answer:
B
Step-by-step explanation:
Basically, this question is asking the legs of the triangle shown in the graph.
In this right triangle, there are 2 legs and one of them is 6400 meters. We were asked to find out the length of the other led. And we know the angle is 16.5 deg.
Using Tangent to find out:
set the length of the other leg is x meters.
tan(16.5) = 6400/x
x= 6400/tan(16.5)
x= 21606 m
First it shows 33 points and ok
