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3 years ago

10

The cost of a bagel and a cup of coffee is $1.45. The cost of 3 bagels and a cup of coffee is $2.95. What is the cost of a cup o

f coffee?

1 answer:

seropon [69]3 years ago

8 0

<em> </em><em>The</em><em> </em><em>answer</em><em> </em><em>is</em><em> </em><em>0</em><em>.</em><em>7</em><em>5</em><em>.</em><em>Hope</em><em> </em><em>this</em><em> </em><em>will</em><em> </em><em>help</em><em> </em><em>u</em><em>.</em><em>.</em><em>.</em><em>.</em>

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The students lockers at a college are to be numbered consecutively form 1 to 800 using plastic digits. Each digit cost 10c. What

KIM [24]

Answer would be eight because you divide eight hundred by ten cents to get eight.

6 0

3 years ago

If y varies directly as x^2 and y=12 when x=2, find y when x=5

Shkiper50 [21]

$y=ax^2\\\\y=12\ \ \ and\ \ \ x=2\ \ \ \Rightarrow\ \ \ 12=a\cdot 2^2\ \ \ \Rightarrow\ \ \ a= \frac{4}{12}= \frac{1}{3} \\\\y=\frac{1}{3} x^2\\\\x=5\ \ \ \Rightarrow\ \ \ y=\frac{1}{3} \cdot5^2=\frac{25}{3} =8\frac{1}{3}$

7 0

3 years ago

Someone help me please !!!

KIM [24]

Answer:

1. 10

2. 12

3. Sqrt 130

4. Sqrt 45

Step-by-step explanation:

To find the missing side of a right triangle, use the Pythagorean Theorem. The Pythagorean Theorem is $a^2+b^2=c^2$ where a and b are the legs with a being the smallest and c is the hypotenuse.

1. a=6, b=8, c=?

$6^2+8^2=c^2\\36+64=c^2\\100=c^2\\10=c$

2. a=5, b=?, c=13

$5^2+b^2=13^2\\25+b^2=169\\169-25=b^2\\144=b^2\\12=b$

3. a=7, b=9, c=?

$7^2+9^2=c^2\\49+81=c^2\\130=c^2\\\sqrt{130}=c$

4. a=2, b=?, c=7

$2^2+b^2=7^2\\4+b^2=49\\49-4=b^2\\45=b^2\\\sqrt{45}=b$

5 0

3 years ago

Kryptonite is a material found on the planet Krypton and has various effects, most importantly on Superman. The most common type

Rashid [163]

Answer:

The maximum amount of red kryptonite present is 33.27 g after 4.93 hours.

Step-by-step explanation:

dy/dt = y(1/t - k)

separating the variables, we have

dy/y = (1/t - k)dt

dy/y = dt/t - kdt

integrating both sides, we have

∫dy/y = ∫dt/t - ∫kdt

㏑y = ㏑t - kt + C

㏑y - ㏑t = -kt + C

㏑(y/t) = -kt + C

taking exponents of both sides, we have

$\frac{y}{t} = e^{-kt + C} \\\frac{y}{t} = e^{-kt}e^{C} \\\frac{y}{t} = Ae^{-kt} (A = e^{C})\\y = Ate^{-kt}$

when t = 1 hour, y = 15 grams. So,

$y = Ate^{-kt}\\15 = A(1)e^{-kX1}\\15 = Ae^{-k}$ (1)

when t = 3 hours, y = 30 grams. So,

$y = Ate^{-kt}\\30 = A(3)e^{-kX3}\\30 = 3Ae^{-3k}$ (2)

dividing (2) by (1), we have

$\frac{30}{15} = \frac{3Ae^{-3k}}{Ae^{-k}} \\2 = 3e^{-2k}\\\frac{2}{3} = e^{-2k}$

taking natural logarithm of both sides, we have

-2k = ㏑(2/3)

-2k = -0.4055

k = -0.4055/-2

k = 0.203

From (1)

$A = 15e^{k} \\A = 15e^{0.203} \\A = 15 X 1.225\\A = 18.36$

Substituting A and k into y, we have

$y = 18.36te^{-0.203t}$

The maximum value of y is obtained when dy/dt = 0

dy/dt = y(1/t - k) = 0

y(1/t - k) = 0

Since y ≠ 0, (1/t - k) = 0.

So, 1/t = k

t = 1/k

So, the maximum value of y is obtained when t = 1/k = 1/0.203 = 4.93 hours

$y = 18.36(1/0.203)e^{-0.203t}\\y = \frac{18.36}{0.203}e^{-0.203X1/0.203}\\y = 90.44e^{-1}\\y = 90.44 X 0.3679\\y = 33.27 g$

<u>So the maximum amount of red kryptonite present is 33.27 g after 4.93 hours.</u>

3 0

3 years ago

6 4/9 + 14 2/3= <br><br><br> 5 1/4 – 3 3/5 =

dimulka [17.4K]

<em>Refer to the attachments!!</em><em>~</em>

8 0

2 years ago

Read 2 more answers