You bought a magazine for $5 and four erasers. You spent a total of $25. How much did each eraser cost?

Increase $32 in the ratio 2:5<br>decrease 54 litter in the ratio 5:1<br>

Novay_Z [31]

Answer:

Step-by-step explanation:

32 = 2 : 5

32/7 = 4

2 x 4 : 4 x 5

8 : 20

8 0

2 years ago

Gary made 5 baskets than Susan this season bill made 3 less then twice as many baskets as Susan. Together, all three made 42 bas

Nezavi [6.7K]

Answer:Gary made 15 baskets.

Susan made 10 baskets.

Bill made 17 baskets.

Step-by-step explanation:

Let x represent the number of baskets that Gary made.

Let y represent the number of baskets that Susan made.

Let z represent the number of baskets that Bill made.

Gary made 5 baskets than Susan this season. This means that

x = y + 5

Bill made 3 less than twice as many baskets as Susan. This means that

z = 2y - 3

Together, all three made 42 baskets. This means that

x + y + z = 42 - - - - - - - - - - 1

Substituting x = y + 5 and z = 2y - 3 into equation 1, it becomes

y + 5 + y + 2y - 3 = 42

4y + 2 = 42

4y = 42 - 2 = 40

y = 40/4 = 10

x = y + 5 = 10 + 5

x = 15

z = 2y - 3 = 2 × 10 - 3

z = 20 - 3 = 17

3 0

3 years ago

Problem 10: A tank initially contains a solution of 10 pounds of salt in 60 gallons of water. Water with 1/2 pound of salt per g

AysviL [449]

Answer:

The quantity of salt at time t is $m_{salt} = (60)\cdot (30 - 29.833\cdot e^{-\frac{t}{10} })$ , where t is measured in minutes.

Step-by-step explanation:

The law of mass conservation for control volume indicates that:

$\dot m_{in} - \dot m_{out} = \left(\frac{dm}{dt} \right)_{CV}$

Where mass flow is the product of salt concentration and water volume flow.

The model of the tank according to the statement is:

$(0.5\,\frac{pd}{gal} )\cdot \left(6\,\frac{gal}{min} \right) - c\cdot \left(6\,\frac{gal}{min} \right) = V\cdot \frac{dc}{dt}$

Where:

$c$ - The salt concentration in the tank, as well at the exit of the tank, measured in $\frac{pd}{gal}$ .

$\frac{dc}{dt}$ - Concentration rate of change in the tank, measured in $\frac{pd}{min}$ .

$V$ - Volume of the tank, measured in gallons.

The following first-order linear non-homogeneous differential equation is found:

$V \cdot \frac{dc}{dt} + 6\cdot c = 3$

$60\cdot \frac{dc}{dt} + 6\cdot c = 3$

$\frac{dc}{dt} + \frac{1}{10}\cdot c = 3$

This equation is solved as follows:

$e^{\frac{t}{10} }\cdot \left(\frac{dc}{dt} +\frac{1}{10} \cdot c \right) = 3 \cdot e^{\frac{t}{10} }$

$\frac{d}{dt}\left(e^{\frac{t}{10}}\cdot c\right) = 3\cdot e^{\frac{t}{10} }$

$e^{\frac{t}{10} }\cdot c = 3 \cdot \int {e^{\frac{t}{10} }} \, dt$

$e^{\frac{t}{10} }\cdot c = 30\cdot e^{\frac{t}{10} } + C$

$c = 30 + C\cdot e^{-\frac{t}{10} }$

The initial concentration in the tank is:

$c_{o} = \frac{10\,pd}{60\,gal}$

$c_{o} = 0.167\,\frac{pd}{gal}$

Now, the integration constant is:

$0.167 = 30 + C$

$C = -29.833$

The solution of the differential equation is:

$c(t) = 30 - 29.833\cdot e^{-\frac{t}{10} }$

Now, the quantity of salt at time t is:

$m_{salt} = V_{tank}\cdot c(t)$

$m_{salt} = (60)\cdot (30 - 29.833\cdot e^{-\frac{t}{10} })$

Where t is measured in minutes.

7 0

3 years ago

I’m stuck with this question :(

gayaneshka [121]

Answer:

The same number was not added to both sides.

Step-by-step explanation:

Given:

t - 8 = 65

in the next step it states something wrong, because it should have been this:

t - 8 = 65

add +8 left and right of the = sign.

t - 8 + 8 = 65 + 8

t + 0 = 73

t = 73

So the error made what's that

The same number was not added to both sides.

8 0

3 years ago

Read 2 more answers

Please help i will give brainliest

inysia [295]

Answer:

Step-by-step explanation:

Take the area of the yard and subtract from it the area of the pool. In quadratic form, the area of the pool is

$2x^2-x-28$

Subtracting the area of the pool from the area of the yard:

$3x^2-14x-5-(2x^2-x-28)$

Since the negative in front of the parenthesis will change the signs inside:

$3x^2-14x-5-2x^2+x+28$

Combine like terms to get the area left after the pool goes in:

$x^2-13x+23$

8 0

3 years ago