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2 years ago

How much water should we add to 20 kg of seawater to change its concentration from 3% to 2%?

Mathematics

1 answer:

zhannawk [14.2K]2 years ago

6 0

Answer:

10 kg

Step-by-step explanation:

In 3% concentration of 20 kg of seawater, there will be $\frac{20 \times 3}{100} = 0.6$ kg of salt.

So, if it is a 2% solution of seawater,

Then 2 kg salt will be there in 100 kg solution.

So, 0.6 kg salt will be there in $\frac{100 \times 0.6}{2}= 30$ kg of solution.

So, to make a solution from 3% to 2% we have to add (30 - 20) = 10 kg of water with a 20 kg solution. (Answer)

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$22.50 is the cost of 15 tomatoes

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3 years ago

Please answer question three and four if you can :)<br> Show full working out ty;)

nikklg [1K]

Step-by-step explanation:

Let D be the mid point of side BC, [B(2, - 1), C(5, 2)].

Therefore, by mid-point formula:

$D = ( \frac{2 + 5}{2}, \: \: \frac{ - 1 + 2}{2} ) = ( \frac{7}{2}, \: \: \frac{ 1}{2} ) \\ \therefore D= (3.5, \: \: 0.5) \\ \& \: A=(-1,\:\:4)...(given) \\\\ now \: by \: distance \: formula \\ \\ Length \: of \: segment \: AD \\ = \sqrt{( - 1 - 3.5)^{2} + {(4 - 0.5)}^{2} } \\ = \sqrt{(4.5)^{2} + {(3.5)}^{2} } \\ = \sqrt{20.25 + 12.25 } \\ = \sqrt{32.5} \\ \red{ \boxed{\therefore Length \: of \: segment \: AD = 5.7 \: units}}$

4 (a)

Equation of line AB[A(2, 1), B(-2, - 11)] in two point form is given as:

$\frac{y-y_1}{y_1-y_2} =\frac{x-x_1}{x_1 - x_2} \\\\\therefore \frac{y-1}{1-(-11)} =\frac{x-2}{2 - (-2) } \\\\\therefore \frac{y-1}{1+11} =\frac{x-2}{2 +2} \\\\\therefore \frac{y-1}{12} =\frac{x-2}{4} \\\\\therefore \frac{y-1}{3} =\frac{x-2}{1} \\\\\therefore y-1= 3(x - 2)\\\\\therefore y= 3x - 6+1\\\\\therefore y= 3x - 5\\\\ \huge \purple {\boxed {\therefore 3x - y-5=0}} \\$

is the equation of line AB.

Now we have to check whether C(4, 7) lie on line AB or not.

Let us substitute x = 4 & y = 7 on the Left hand side of equation of line AB and if it gives us 0, then C lies on the line.

$LHS = 3x - y-5\\=3\times 4-7-5\\= 12-12\\=0\\= RHS$

Hence, point C (4, 7) lie on the straight line AB.

4(b)

Like we did in 4(a), first find the equation of line AB and then substitute the coordinates of point C in equation and if they satisfy the equation, then all the three points lie on the straight line.

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3 years ago

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Step-by-step explanation: GIVE ME BRAINLY A VOTE AND A THANKS BYE

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3 years ago

One morning during the spring break, Jose ran 13 miles up hill in the rain. That afternoon Jose ran up the hill 3 2/3 faster whe

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Answer:

The answer to your question is 13 miles

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In the question is not mentioned the distance that Jose one during the afternoon, it is only mentioned that he ran faster than in the morning so we can imply that the distance was the same in both occasions, just he ran faster in the afternoon because there was no rain.

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3 years ago

Find the surface area of the cylinder to the nearest tenth of a square unit. use 3.14 for pi

Alborosie

Given: