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valentina_108 [34]
3 years ago
8

A boat can travel 21mph in still water. If it travels 270 miles with the current in the same length of time it travels 108 miles

against the current, what is the speed of the current?
Mathematics
1 answer:
erica [24]3 years ago
7 0

Answer: the speed of the current is 9 mph.

Step-by-step explanation:

Let x represent the speed of the current.

A boat can travel 21 mph in still water. If it travels 270 miles with the current. It means that the total speed with which the boat travelled with the current is (21 + x) mph.

Time = distance/speed

Time spent by the boat in travelling 270 miles is

270/(21 + x)

In the same length of time, it travels 108 miles against the current. It means that the total speed with which the boat travelled against the current is (21 - x) mph.

Time = distance/speed

Time spent by the boat in travelling 108 miles is

108/(21 - x)

Since the time is the same, then

270/(21 + x) = 108/(21 - x)

270(21 - x) = 108(21 + x)

5670 - 270x = 2268 - 108x

108x + 270x = 5670 - 2268

378x = 3402

x = 3402/378

x = 9

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lidiya [134]

Answer:

y=4x-3

Step-by-step explanation:

Parallel lines will always have the same slope (the number that comes before x in an equation). So, we can plug in 4 to the equation.

y=4x+?

Let's say the ? is b. If we plug in the point (1,1) into y=4x+b, we get

1=4(1)+b

reduce

1=4+b

subtract 4 from both sides

-3=b

and now we can add b=-3 into the original answer, and we get y=4x-3!

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3 years ago
Find the equation of the line that goes through (-8,11) and is perpendicular to x= - 15. Write the equation in the form x = a, y
galben [10]

Answer:

y=11

Step-by-step explanation:

Hi there!

We want to find the equation of the line that passes through the point (-8, 11) and is perpendicular to x=-15

If a line is perpendicular to another line, it means that the slopes of those lines are negative and reciprocal; in other words, the product of the slopes is equal to -1

The line x=-15 has an undefined slope, which we can represent as 1/0, which is also undefined.

To find the slope of the line perpendicular to x=-15, we can use this equation (m is the slope):

m_1*m_2=-1

m_1 in this instance would be 1/0, so we can substitute it into the equation:

\frac{1}{0} *m_2=-1

Multiply both sides by 0

m_2=0

So the slope of the new line is 0

We can substitute it into the equation y=mx+b, where m is the slope and b is the y intercept:

y=0x+b

Now we need to find b:

Since the equation passes through the point (-8,11), we can use its values to solve for b.

Substitute -8 as x and 11 as y:

11=0(-8)+b

Multiply

11=0+b, or 11=b

So substitute into the equation:

y=0x+11

We can also write the equation as y=11

Hope this helps!

5 0
3 years ago
cert 22.2 U To 3. Draw an area diagram to find (0.36) (0.53). Label and organize your work so that it can be followed by others.
Masteriza [31]

The result of the product of (0.36) and (0.53) is 0.1908

<h3>How to determine the product</h3>

The product expression is given as:

(0.36) * (0.53)

Rewrite the product as follows:

(0.36) * (0.53) = (0.3 + 0.06) * (0.5 + 0.03)

Expand the product

(0.36) * (0.53) = 0.3 * (0.5 + 0.03)+ 0.06 * (0.5 + 0.03)

Expand

(0.36) * (0.53) = 0.15 + 0.009+ 0.03+ 0.0018

Evaluate the sum

(0.36) * (0.53) = 0.1908

See attachment for the area diagram of the product

Read more about products at:

brainly.com/question/10873737

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1 year ago
BRAINLIEST!!! Plz help ASAP
Svetllana [295]

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y coordinates- (9+y)/2=7

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And therefore R is (4, 5)

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hodyreva [135]

Answer:

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Step-by-step explanation:

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