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2 years ago

when heated an iron bar expands by 0.2 %.if the increase in length 1 cm, what is the original length of the bar?

Mathematics

1 answer:

gregori [183]2 years ago

5 0

0.2% = 2/100

increase amount over the whole amount

If the increase length is 1cm and you are looking for the whole amount

2/100 = 1/x

Cross multiply
2x = 100
x = 50 cm is the original length of the bar

Checking you answer,
0.2% of 50 is 0.02 × 50 which is 1 so the answer is correct.

The original length of the bar is 50 cm.

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A tank contains 8000 L of pure water. Brine that contains 35 g of salt per liter of water is pumped into the tank at a rate of 2

OleMash [197]

Answer:

The concentration of salt in the tank approaches $35 \mathrm{g} / \mathrm{L},$

Step-by-step explanation:

Data provide in the question:

Water contained in the tank = 8000 L

Salt per litre contained in Brine = 35 g/L

Rate of pumping water into the tank = 25 L/min

Concentration of salt $\lim _{t \rightarrow \infty} C(t)=\lim _{t \rightarrow \infty} \frac{35 t}{320+t}$

Now,

Dividing both numerator and denominator by $t$ , we have

$\lim _{t \rightarrow \infty} \frac{\frac{1}{t} 35 t}{\frac{1}{t}(320+t)}=\lim _{t \rightarrow \infty} \frac{35}{\frac{320}{t}+1}=35$

Here,

The concentration of salt in the tank approaches $35 \mathrm{g} / \mathrm{L},$

3 0

2 years ago

A community hall is in the shape of a cuboid the hall is 40m long 15m high and 3m wide. 10 litre paint covers 25m squared costs

Darina [25.2K]

Answer:

Total cost for tiles and paints is $924.

Step-by-step explanation:

We have been given that a community hall is in the shape of a cuboid. The hall is 40m long 15m high and 3m wide.

The paint will be required for 4 walls and ceiling.

Let us find area of walls and ceiling.

$\text{Area of walls and ceiling}=(2*40*15)+(2*3*15)+(40*3)$

$\text{Area of walls and ceiling}=1200+90+120$

$\text{Area of walls and ceiling}=1410$

Therefore, the area of walls and ceiling is 1410 square meters.

Given: Cost for 10 litre of paint is $10 and 10 litre paint covers 25 square meter. Therefore,

$\text{ The total painting cost}=10*(\frac{1410}{25})$

$\text{ The total painting cost}=10*56.4=564$

Therefore, the total painting cost is $564.

Tiles will be required for floor. Let us find the area of floor.

$\text{Area of floor} = 40*3\text{ square meters}$

$\text{Area of floor} =120\text{ square meters}$

Given: 1m squared floor tiles costs $3. So,

$\text{Total cost for tiles} = 3*120 = 360$

Therefore, the total tiles cost is $360.

Now let us find combined total cost of tiles and paint.

$\text{Combined total cost}= 564+360 = 924$

Therefore, the combined total cost of tiles and paint is $924.

6 0

2 years ago

Tony’s class needs more than $500 for the school dance. So far, they have raised $200. They plan to have a car wash, charging $8

Orlov [11]

Answer: no Tony is not correct It is less than 5 hundred dollars.

Step-by-step explanation: 8×37=296 +200 = 496

4 0

2 years ago

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The value of an autographed baseball from 2017 is $300. The value of the baseball exponentially increases by 5% each year after

WARRIOR [948]

General exponential equation
y = A(1+r)^x
where
A = initial value
r = rate increase (+) or decrease (-)
x = time period of the change
y = projected value

y = 300(1.05)^x
in this problem, x = years after 2017
we want to find an x that makes the value more than or equal to 650

650 <= 300(1.05)^x

7 0

2 years ago

A country's population in 1993 was 94 million. in 1999 in was 99 million. estimate the population in 2005 using the exponential

Jet001 [13]

The initial population is
P₀ = 94 million in 1993

The growth formula is
$P(t) = P_{0}e^{kt}$
where P(t) is the population (in millions) after t years, measured from 1993.
k = constant.

Because P(5) = 99 million (in 1999),
$94e^{5k} = 99 \\e^{5k}=1.0532 \\ 5k = ln(1.0532) \\ k = 0.010367$

In the year 2005, t = 12 years, and
$P(12)=94e^{0.010367*12} = 106.45$

Answer: 106 million (nearest million)

7 0

1 year ago