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2 years ago

Solve for k? Please help me

Mathematics

1 answer:

Lisa [10]2 years ago

3 0

Check the picture below.

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If 12 workers can dig a tunnel in 100 days, how long will it take 20 workers to dig the tunnel

Paraphin [41]

Answer:

60 days.

Step-by-step explanation:

This is a proportion question. You compare two ratios. Unfortunately it is an inverse ratio.

12 = k/100 Multiply both sides by 100

1200 = k

20 = k/x Multiply both sides by x

20x = k

20x = 1200 Divide by 20

20x/20 = 1200/20

x = 60 days.

An inverse proportion works by making a constant k. The constant k makes the days shorter when the number of people increases. You should expect that. More people , less time.

3 0

2 years ago

I am VERY confused on this question. Can someone help me?

Iteru [2.4K]

Answer: z=67-at
————
a-45

6 0

3 years ago

A car is being driven at a rate of 40 ft/sec when the brakes are applied. The car decelerates at a constant rate of 10 ft/sec2.

IRISSAK [1]

Answer:

80 feet

Step-by-step explanation:

Given:

Initial speed of the car ( $v_0$ ) = 40 ft/sec

Deceleration of the car ( $\frac{dv}{dt}$ ) = -10 ft/sec²

Final speed of the car ( $v_x$ ) = 0 ft/sec

Let the distance traveled by the car be 'x' at any time 't'. Let 'v' be the velocity at any time 't'.

Now, deceleration means rate of decrease of velocity.

So, $\frac{dv}{dt}=-10\ ft/sec^2$

Negative sign means the velocity is decreasing with time.

Now, $\frac{dv}{dt}=\frac{dv}{dx}(\frac{dx}{dt})$ using chain rule of differentiation. Therefore,

$\frac{dv}{dx}\cdot\frac{dx}{dt}= -10\\\\But\ \frac{dx}{dt}=v.\ So,\\\\v\frac{dv}{dx}=-10\\\\vdv=-10dx$

Integrating both sides under the limit 40 to 0 for 'v' and 0 to 'x' for 'x'. This gives,

$\int\limits^0_{40} {v} \, dv=\int\limits^x_0 {-10} \, dx\\\\\left [ \frac{v^2}{2} \right ]_{40}^{0}=-10x\\\\-10x=\frac{0}{2}-\frac{1600}{2}\\\\10x=800\\\\x=\frac{800}{10}=80\ ft$

Therefore, the car travels a distance of 80 feet before stopping.

4 0

2 years ago

The midpoint of AB is M(0,2). If the

otez555 [7]

Answer:

Step-by-step explanation:

(x+2)/2 = 0

x + 2 = 0

x = -2

(y - 3)/2 = 2

y - 3 = 4

y = 7

(-2, 7)

8 0

2 years ago

Which fraction equals 0.5? A.1/8 B.4/8 C.4/4 D.4/10 Plz Help!!!!!!!

faltersainse [42]

Its B because 4 is half of 8

5 0

2 years ago

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