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3 years ago

15

Megan bought 3 pounds of apples that cost dollars per pound. She gave the cashier a 20-dollar bill. Which equation could Megan u

se to find the amount of change y, she should receive

1 answer:

Phantasy [73]3 years ago

8 0

Answer:

3x-20 or x=6.6 but Im not sure.

Step-by-step explanation:

You might be interested in

What is the measure in radians for the central angle of a circle whose radius is 9 cm and intercepted arc length is 7.2 cm?

siniylev [52]

Arc length = radius * central angle (in radians)
central angle (in radians) = arc length / radius
central angle (in radians) = 7.2 / 9
=.8 radians

4 0

3 years ago

Read 2 more answers

A similar scale model of a building is 12 in tall and 9 in wide. If the actual building is 100 ft tall, how wide is the building

Dmitry [639]

You just put the scale of one building on one side and the scale of the similar building on other side, with width and length written in same place (denominator or numerator). With x for the part that you dont know

Length of one building / width of one building = length of other building / width of other building

12 / 9 = 100 / x

Solve for x, by cross-multiplying

12 * x = 100 * 9
12x = 900
X = 900/12
X = 75 ft

4 0

2 years ago

The perimeter of the cover of a math textbook is 34 inches. if the width of the cover is 7 inches, what is the length of the cov

Sauron [17]

The length would be 10 inches.
to find perimeter, you add length+length+width+width.
since both widths and both lengths have to be the same, u add the width 2 times or 7+7=14.
next u subtract 14 from 34 or 34-14=20.
since u still have 2 lengths that are equal, u divide 20 by 2 or 20/2=10

hope this helps! :)

7 0

3 years ago

This is the pond in a shape of a prism, it is completely full of water. Colin uses a pump to empty the pond. The level goes down

AnnZ [28]

Answer:

150 minutes

Step-by-step explanation:

P.S - The exact question is -

Given - This is the pond in a shape of a prism, it is completely full of

water. Colin uses a pump to empty the pond. The level goes

down by 20 cm in the first 30 min.

To find - Work put how many minutes Colin has to wait for the pond

to completely empty.

Proof -

Given that,

Height of prism = 1 m

Also,

Base of the prism is trapezium and

Sides of the trapezium are 0.6 m and 1.4 m

Height of trapezium is 2 m

We know that,

Area of trapezium = $\frac{1}{2}$ × (sum of sides)× height

= $\frac{1}{2}$ × (0.6 + 1.4)× 2

= $\frac{1}{2}$ × (2)× 2

= 2 m²

⇒Area of trapezium = 2 m²

Now,

Volume of prism = Area of trapezium × height of prism

= 2 m² × 1 m

= 2 m³

⇒Volume of prism = 2 m³

Now,

Given that the level goes down by 20 cm in the first 30 min

We know

100 cm = 1 m

⇒1 cm = $\frac{1}{100} m$ = 0.01 m

⇒20 cm = 20×0.01 m = 0.2 m

⇒The level goes down by 0.2 m in the first 30 min.

Also,

we know that height of water = height of prism = 1 m

So, the remaining water left in the pond = 1 m - 0.2 m = 0.8 m

Also,

Volume of Remaining water = Area of trapezium × height

= 2 m² × 0.8 m

= 1.6 m³

⇒Volume of Remaining water = 1.6 m³

Now,

Volume of emptied water = Total Volume - Volume of Remaining water

= 2 m³ - 1.6 m³

= 0.4 m³

⇒Volume of emptied water = 0.4 m³

Now,

0.4 m³ water will be empty in 30 minutes

⇒ 1 m³ water will be empty in $\frac{30}{0.4}$ = 75 minutes

⇒1.6 m³ water will be empty in 1.6 × 75 = 120 minutes

∴ we get

The remaining water is empty in 120 minutes

So,

Total pond is empty in 120 + 30 minutes

⇒Total pond is empty in 150 minutes

5 0

3 years ago

A roast turkey is taken from an oven when its temperature has reached 185 degrees F and is placed on a table in a room where the

Vedmedyk [2.9K]

(a) Using Newton's Law of Cooling, $\dfrac{dT}{dt} = k(T - T_s)$ , we have $\dfrac{dT}{dt} = k(T - 75)$ where T is temperature after T minutes.
Separate by dividing both sides by T - 75 to get $\dfrac{dT}{T - 75} = k dt$ . Integrate both sides to get $\ln|T - 75| = kt + C$ .

Since $T(0) = 185$ , we solve for C:
$|185 - 75| = k(0) + C\ \Rightarrow\ C = \ln 110$
So we get $\ln|T - 75| = kt + \ln 110$ . Use T(30) = 150 to solve for k:
$\ln| 150 - 75 | = 30k + \ln 110\ \Rightarrow\ \ln 75 - \ln 110= 30k \Rightarrow \\ k= \frac{1}{30}\ln (75/110) = \frac{1}{30}\ln(15/22)$

So

$\ln|T - 75| = kt + \ln 110 \Rightarrow |T - 75| = e^{kt + \ln110} \Rightarrow \\ \\
|T - 75| = 110e^{kt} \Rightarrow T - 75 = \pm110e^{(1/30)\ln(15/22)t} \Rightarrow \\
T = 75 \pm110e^{(1/30)\ln(15/22)t}$

But choose Positive because T > 75. Temp of turkey can't go under.

$T(t) = 75 + 110e^{(1/30)\ln(15/22)t} \\
T(45) = 75 + 110e^{(1/30)\ln(15/22)(45)} = 136.929 \approx 137{}^{\circ}F$

(b)

$T(t) = 75 + 110e^{(1/30)\ln(15/22)t} = 75 + 110(15/22)^{t/30} \\
100 = 75 + 110(15/22)^{t/30} \\
25 = 110(15/22)^{t/30} 
\frac{25}{110} = (15/22)^{t/30} \\
\ln(25/110) / ln(15/22) = t/30 \\
t = 30\ln(25/110) / ln(15/22) \approx 116\ \mathrm{min}$

Dogs of the AMS.

4 0

3 years ago