Who had the quickest average time per mile?

There are 24 pictures on a roll of film. Adelle had 84 pictures from her trip home. She said that 12 other pictures were spoiled

sattari [20]

Adelle used three rolls of film.

8 0

4 years ago

Read 2 more answers

HELP PLEASE!

Dima020 [189]

X = the number of minutes the phone is used

Plan A:
40¢ per minute ($0.40)
no other costs
Cost for 1 month = 0.4 x

Plan B:
$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: Cost = 30


If 'x' is greater than 100:

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:  Cost = 0.5x - 20

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.

If you use the phone for less than 100 minutes a month,
(where the cost of Plan B starts increasing with each minute):

0.4x = 30

Divide each side by 0.4: x = 75

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.

If you use the phone for more than 100 minutes a month: 

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:  200 = x

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.

8 0

3 years ago

Plz help me ASAP thx.

kolbaska11 [484]

Use the Pythagorean theorem:

$a^2+(2\sqrt3)^2=(4\sqrt3)^2\\\\a^2+2^2(\sqrt3)^2=4^2(\sqrt3)^2\\\\a^2+4\cdot3=16\cdot3\\\\a^2+12=48\ \ \ \ |-12\\\\a^2=36\to a=\sqrt{36}\\\\\boxed{a=6\to C.}$

Used:

$(a\cdot b)^n=a^n\cdot b^n\\\\(\sqrt{a})^2=a$

3 0

3 years ago

Solve 2r ≤ 3(2r - 7)

Hoochie [10]

You have:
2r $\leq$ 6r-21
then move the 6r over to the left and you end up wtih
-4r $\leq$ -21
Then you divide by -4 and when you do you must flip the inequality so your answer would be
r $\geq$ 21/4

8 0

3 years ago

Read 2 more answers

For the equation, 9x = 3y. Write an EQUATION describing y as a function of x

aleksandr82 [10.1K]

Answer: 9x + 3y = 12

Alternative forms: y = 0.4 OR y = $2/3^{2}$

6 0

2 years ago