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3 years ago

If there are 91 seats in 7 rows how many seats are in 4 rows

Mathematics

2 answers:

MakcuM [25]3 years ago

5 0

Answer:

It would be 52

Step-by-step explanation:

You divide 91 by 7 and u get 13 so u multiply that by 4 and u get your answer

irina1246 [14]3 years ago

4 0

I believe the answer is 52

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A stool of ribbon holds 6.75 meters.A craft club buys 21 stools. What is the total cost if the ribbon sells for $2 per meter.

OLEGan [10]

283.5

So you multiply 6.75 by 21 stools to find the total number of meters. Then you multiply that by 2.

7 0

3 years ago

Jay sells 10 packs of apples for 80p. He wants to make £75 at the end of the year. How many packs of apples does he need to sell

ipn [44]

Answer:

937.5 packs of apples

Step-by-step explanation:

Note that:

100p = £1

80p = x

Cross Multiply

100x = 80p × £1

x = 80/100

x = £0.8

Jay sells 10 packs of apples for 80p.

Hence:

£0.8 = 10 packs of apples

£75 = x

Cross Multiply

£0.8 × x = £75 × 10 Packs

x = £75 × 10 Packs/£0.8

x = 937.5

Therefore, to make £75 at the end of the year, he has to sell 937.5 packs of apples

3 0

2 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

Each day in Bio 18, Derek leaves a stack of paper packets near the entry door for students to obtain. Eighty-one percent of stud

Rainbow [258]

Answer:

Step-by-step explanation:

This is a binomial probability distribution because there are only 2 possible outcomes. It is either a randomly selected student grabs a packet before being seated or the student sits first before grabbing a packet. The probability of success, p in this scenario would be that a randomly selected student sits first before grabbing a packet. Therefore,

p = 1 - 0.81 = 0.91

n = 9 students

x = number of success = 3

The probability that exactly two students sit first before grabbing a packet, P(x = 2) would be determined from the binomial probability distribution calculator. Therefore,

P(x = 2) = 0.297

5 0

3 years ago

82.8 cm measured to the nearest tenth of a cm <br><br> what's the answer<br><br> ;-)

patriot [66]

Answer:

I think it 8.0 cm

7 0

3 years ago

Read 2 more answers