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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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Factor the trinomial:<br> 3x2 + 13x + 12
yarga [219]

Answer:

Step-by-step explanation:

(3x + 4)(x + 3)

3x^2 + 9x + 4x + 12

3x^2 + 13x + 12

8 0
3 years ago
What is the value of x in the equation 1.5(x + 4) – 3 = 4.5(x – 2)? 3 4 5 9
ICE Princess25 [194]

1.5(x+4)-3=4.5(x-2)

First, distribute 1.5 into x and 4, and 4.5 into x and -2, to get rid of the parentheses. Everything that we do to solve this equation is to isolate x to solve for its value.

1.5x+6-3=4.5x-9

Combine like terms on both sides (6-3).

1.5x+3=4.5x-9

Subtract 1.5x from both sides.

3=3x-9

Add 9 to both sides.

12=3x

Divide both sides by 3.

4=x

The answer is 4.

I hope this helps :)

7 0
3 years ago
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A recipe calls for 3 times as many chocolate chips as butterscotch chips. If there are 25 oz of chocolate chips, how many oz do
Bingel [31]

The amount, in oz of butterscotch chips needed by proportional reasoning is; 75oz.

<h3>What is the amount of butterscotch chips needed by proportional reasoning?</h3>

It follows from the task content that the the amount of butterscotch chips needed can be determined by means of the proportion premise declared in which case;

  • The recipe requires 3 times as many chocolate chips as butterscotch chips.

Hence, when 25oz of chocolate chips is used, the amount of butterscotch needed is 3 times 25 and hence, = 3 × 25 = 75oz.

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4 0
2 years ago
Molly was on a long 136 mile road trip. The first part of the trip there was lots of traffic, she only averaged 16 mph. The seco
Mazyrski [523]

Answer:

In traffic, she drove for 3 hours

and After the traffic cleared she drove for 2 hours.

Explanation:

Given that the road trip was 136 miles;

d=136

The first part of the trip there was lots of traffic, she only averaged 16 mph;

v_1=16

The second part of the trip there was no traffic so she could drive 44 mph;

v_2=44

She traveled for a total of 5 hours;

t=5

let x represent the time in traffic when she traveled at 16 mph

t_1=x

the time the traffic is clear would be;

t_2=t-t_1=5-x

Recall that distance equals speed multiply by time;

d=v_1t_1_{}_{}^{}+v_2t_2

substituting the values;

136=16x+44(5-x)

solving for x;

\begin{gathered} 136=16x+220-44x \\ 44x-16x=220-136 \\ 28x=84 \\ x=\frac{84}{28} \\ x=3 \end{gathered}

So;

\begin{gathered} t_1=3\text{ hours} \\ t_2=5-x=5-3=2 \\ t_2=2\text{ hours} \end{gathered}

Therefore, In traffic, she drove for 3 hours

and After the traffic cleared she drove for 2 hours.

7 0
2 years ago
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