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3 years ago

5

Tom can do a job in 4 hours while Sam can do it in 6 hours. How many hours would it take to complete this job if they work toget

her?

1 answer:

Hunter-Best [27]3 years ago

4 0

Answer:

12/5hours=2.4 hours

Step-by-step explanation:

Sam:6hours

Tom:4hours

This is a rate problem

Sam's rate is one job completed in 6 hours which is 1/6

Tom's rate is one job completed in 4 hours which is 1/4

Together, they could complete 1/4+1/6 of the job in y hours

We are trying to find the rate at which Sam and Tom could complete the job together, or one job in x days, for a rate of 1/y

1/4+1/6=1/y

The least common denominator is 12y

Multiplying through by the LCD which gives:

12y(1/4)+ 12y (1/6)= 12y (1/y)

3y + 2y=12

5y = 12

y=12/5 hours=2.4hours

Therefore it will take 12/5 hours or 2.4 hours to complete the job if they work together

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Find the missing side length

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Answer:

11

Step-by-step explanation:

it's 10 because on the image it gives you the 7 which would be the top half of the side and the 4 would be the bottom so you just and then and get 11

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3 years ago

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According to industry sources, online banking is expected to take off in the near future. The projected number of households (in

Airida [17]

Answer:

(a) The least-square regression line is: $y=4.662+2.709x$ .

(b) The number of households using online banking at the beginning of 2007 is 31.8.

Step-by-step explanation:

The general form of a least square regression line is:

$y=\alpha +\beta x$

Here,

<em>y</em> = dependent variable

<em>x</em> = independent variable

<em>α</em> = intercept

<em>β</em> = slope

(a)

The formula to compute intercept and slope is:

$\begin{aligned} \alpha &= \frac{\sum{Y} \cdot \sum{X^2} - \sum{X} \cdot \sum{XY} }{n \cdot \sum{X^2} - \left(\sum{X}\right)^2} \\\beta &= \frac{ n \cdot \sum{XY} - \sum{X} \cdot \sum{Y}}{n \cdot \sum{X^2} - \left(\sum{X}\right)^2} \end{aligned}$

The values of ∑<em>X</em>, ∑<em>Y</em>, ∑<em>XY</em> and ∑<em>X</em>² are computed in the table below.

Compute the value of intercept and slope as follows:

$\begin{aligned} \alpha &= \frac{\sum{Y} \cdot \sum{X^2} - \sum{X} \cdot \sum{XY} }{n \cdot \sum{X^2} - \left(\sum{X}\right)^2} = \frac{ 68.6 \cdot 55 - 15 \cdot 218.9}{ 6 \cdot 55 - 15^2} \approx 4.662 \\ \\\beta &= \frac{ n \cdot \sum{XY} - \sum{X} \cdot \sum{Y}}{n \cdot \sum{X^2} - \left(\sum{X}\right)^2} = \frac{ 6 \cdot 218.9 - 15 \cdot 68.6 }{ 6 \cdot 55 - \left( 15 \right)^2} \approx 2.709\end{aligned}$

The least-square regression line is:

$y=4.662+2.709x$

(b)

For the year 2007 the value of <em>x</em> is 10.

Compute the value of <em>y</em> for <em>x</em> = 10 as follows:

$y=4.662+2.709x$

$=4.662+(2.709\times10)\\=4.662+27.09\\=31.752\\\approx 31.8$

Thus, the number of households using online banking at the beginning of 2007 is 31.8.

5 0

3 years ago

Can this please be worked out so I can have a better understanding?

larisa86 [58]

Step-by-step explanation:

no, no, you use the equation to identify a, b and c.

then you use the formula with these values to get the solutions to the equation (the values of x for which the equation delivers 0).

always remember, a quadratic equation always has 2 solutions. sometimes at least one of them are not a real number, sometimes the 2 springs are equal, ...

x² - 4x - 2 = 0

a, b, c are the factors of the terms in x and the constant term.

so,

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b = -4

c = -2

x = (-b ± sqrt(b² - 4ac))/(2a)

x = (4 ± sqrt((-4)² - 4×1×-2))/(2×1) =

= (4 ± sqrt(16 + 8))/2 = (4 ± sqrt(24))/2 =

= (4 ± sqrt(4×6))/2 = (4 ± 2×sqrt(6)) / 2 =

= 2 ± sqrt(6)

x1 = 2 + sqrt(6)

x2 = 2 - sqrt(6)

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2 years ago

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stira [4]

Answer:

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Step-by-step explanation:

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$v(t) = \int a(t) dt$

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$v(t) = (2t+1) \mathbb{i}+3t^2 \mathbb{j} 4t^3 \mathbb{k}$

The position vector is the integral of the velocity vector i.e.

$r(t) = \int v(t) dt$

$r(t) = \int ((2t+1) \mathbb{i}+3t^2 \mathbb{j} 4t^3 \mathbb{k}) dt$

$r(t) = (t^2+t) \mathbb{i}+t^3 \mathbb{j} t^4 \mathbb{k} + C_2$

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4 years ago