4. What is 0.5% of 75??

7. What's the perimeter of a rectangle with length 12 m and width 5 m?

azamat

Answer:

Option(c) 34m

Step-by-step explanation:

Perimeter of a rectangle = 2(length + breadth)

length = 12m

breadth/width = 5m

Perimeter = 2(12 + 5)

= 2(17)

= 34m

8 0

3 years ago

Read 2 more answers

Fill in the Blank 6:15=8:_

Katen [24]

Answer:

20

Step-by-step explanation:

6 0

3 years ago

A swimming pool with a volume of 30,000 liters originally contains water that is 0.01% chlorine (i.e. it contains 0.1 mL of chlo

SpyIntel [72]

Answer:

$R_{in}=0.2\dfrac{mL}{min}$

$C(t)=\dfrac{A(t)}{30000}$

$R_{out}= \dfrac{A(t)}{1500} \dfrac{mL}{min}$

$A(t)=300+2700e^{-\dfrac{t}{1500}},$ A(0)=3000$

Step-by-step explanation:

The volume of the swimming pool = 30,000 liters

(a) Amount of chlorine initially in the tank.

It originally contains water that is 0.01% chlorine.

0.01% of 30000=3000 mL of chlorine per liter

A(0)= 3000 mL of chlorine per liter

(b) Rate at which the chlorine is entering the pool.

City water containing 0.001%(0.01 mL of chlorine per liter) chlorine is pumped into the pool at a rate of 20 liters/min.

$R_{in}=$ (concentration of chlorine in inflow)(input rate of the water)

$=(0.01\dfrac{mL}{liter}) (20\dfrac{liter}{min})\\R_{in}=0.2\dfrac{mL}{min}$

(c) Concentration of chlorine in the pool at time t

Volume of the pool =30,000 Liter

$Concentration, C(t)= \dfrac{Amount}{Volume}\\C(t)=\dfrac{A(t)}{30000}$

(d) Rate at which the chlorine is leaving the pool

$R_{out}=$ (concentration of chlorine in outflow)(output rate of the water)

$= (\dfrac{A(t)}{30000})(20\dfrac{liter}{min})\\R_{out}= \dfrac{A(t)}{1500} \dfrac{mL}{min}$

(e) Differential equation representing the rate at which the amount of sugar in the tank is changing at time t.

$\dfrac{dA}{dt}=R_{in}-R_{out}\\\dfrac{dA}{dt}=0.2- \dfrac{A(t)}{1500}$

We then solve the resulting differential equation by separation of variables.

$\dfrac{dA}{dt}+\dfrac{A}{1500}=0.2\\$The integrating factor: e^{\int \frac{1}{1500}dt} =e^{\frac{t}{1500}}\\$Multiplying by the integrating factor all through\\\dfrac{dA}{dt}e^{\frac{t}{1500}}+\dfrac{A}{1500}e^{\frac{t}{1500}}=0.2e^{\frac{t}{1500}}\\(Ae^{\frac{t}{1500}})'=0.2e^{\frac{t}{1500}}$

Taking the integral of both sides

$\int(Ae^{\frac{t}{1500}})'=\int 0.2e^{\frac{t}{1500}} dt\\Ae^{\frac{t}{1500}}=0.2*1500e^{\frac{t}{1500}}+C, $(C a constant of integration)\\Ae^{\frac{t}{1500}}=300e^{\frac{t}{1500}}+C\\$Divide all through by e^{\frac{t}{1500}}\\A(t)=300+Ce^{-\frac{t}{1500}}$

Recall that when t=0, A(t)=3000 (our initial condition)

$3000=300+Ce^{0}\\C=2700\\$Therefore:\\A(t)=300+2700e^{-\dfrac{t}{1500}}$

3 0

3 years ago

If both the length and width of a rectangle are doubled, how is the area of the rectangle changed?

Law Incorporation [45]

Answer:

B) The area is four times larger

Step-by-step explanation:

$A=LW$

$2*2*A=2L2W$

$4A=2L2W$

Therefore, the area is four times larger

7 0

2 years ago

Devon bought running shocs at a price that was 1/4 off the original price of $88. He paid a sales tax of 7% on

larisa86 [58]

The correct answer is C. $ 9.38

Explanation:

The first step to solve this mathematical problem is to know the price of the shoes. About this, we know the price is 1/4 of $88 plus taxes. You can find how much is 1/4 of $88 by following this process:

1. Write the amounts given

$\frac{1}{4}$ of $88$

2. Divide the number by the denominator (bottom number) and then multiply by the numerator

$88$ ÷ $4 = 22$

$22 x 1 = 22$

This means the discount was $22 and $88- $22 = $66, which is the price with the discount. Now, it is necessary to add the sales tax, which can be done by finding the 7% of $66 and adding this number to $66 (the price of the shoes including the 1/4 discount)

1. Write the values

66 = 100 (66 represents the total or 100%)

x = 7 (7% is the value you want to know and the x represents the value is not known)

2. Cross multiply

x 100 = 462

3. Find x

x = 462 ÷ 100

x = 4. 62 ( value of taxes)

Now, add the taxes to the price $66 + $ 4.62 = $70.62 (price with taxes). Finally, we know Devon paid using four $20 bills. This means he gave the clerk $80 ($20 x 4 = $80). Finally, to know how much is the change subtract the price of the shoes from the money Devon gave the clerk $80 - $70.62 = $9.38

4 0

3 years ago