Which expression is equivalent to 6-(-8)<br> O -6+8<br> O -6+(-8)<br> O 6+(-8)<br> O6+8

B Christian installed an electric pump to pump water from a borehole into a 30 000 litre cement dam. If the water is pumped at a

skelet666 [1.2K]

Given the amount of water needed to fill the cement dam and the water pump rate, the time needed to fill the dam is 400 minutes or 6hours 40minutes.

Option B)6h 40min is the correct answer.

Given that;

Amount of water needed to fill the dam A = 30000 litres
Pump rate r = 75 litres per minute
Time needed to fill the dam T = ?

To determine how long it take to fill the dam, we say;

Time need = Amount of water needed ÷ Pump rate

T = A ÷ r

T = 30000 litres ÷ 75 litres/minute

T = 400 minutes

Note that; 60min = 1hrs

Hence,

T = 6hours 40minutes

Given the amount of water needed to fill the cement dam and the water pump rate, the time needed to fill the dam is 400 minutes or 6hours 40minutes.

Option B)6h 40min is the correct answer.

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2 years ago

1. What is an equation for the line with slope 2/3 and y-intercept 9?

Monica [59]

Question 1:

The generic equation of the line is given by:
$y = mx + b
$
Where,
m: slope of the line
b: cutting point with the y axis
Substituting values we have:
$y = \frac{2}3}x + 9
$
Answer:
an equation for the line with slope 2/3 and y-intercept is:
$y = \frac{2}3}x + 9$

Question 2:

The standard equation of the line is given by:
$y-yo = m (x-xo)
$
Where,
m: slope of the line
(xo, yo): ordered pair that belongs to the line
The slope of the line is:
$m = \frac{y2-y1}{x2-x1}$
Substituting values:
$m = \frac{1-(-3)}{3-1}$
$m = \frac{1+3}{3-1}$
$m = \frac{4}{2}$
$m = 2
$
We choose an ordered pair:
$(xo, yo) = (3, 1)
$
Substituting values:
$y-1 = 2 (x-3)
$
Rewriting:
$y = 2x - 6 + 1

y = 2x - 5$
Answer:
An equation in slope-intercept form for the line that passes through the points (1, -3) and (3,1) is:
$y = 2x - 5
$

Question 3:

For this case, since the variation is direct, then we have an equation of the form:
$y = kx
$ Where,
k: constant of variation.
We then have the following equation:
$-4y = 8x
$ Rewriting we have:
$y = \frac{8}{-4}x
$
$y = -2x
$ Therefore, the constate of variation is given by:
$k = -2
$
Answer:
the constant of variation is:
$k = -2$

Question 4:

For this case, since the variation is direct, then we have an equation of the form:
$y = kx
$ Where,
k: constant of variation.
We must find the constant k, for this we use the following data:
y = 24 when x = 8
Substituting values:
$24 = k8
$ Clearing k we have:
$k = \frac{24}{8} 
$
$k = 3
$
Therefore, the equation is:
$y = 3x
$ Thus, substituting x = 10 we have that the value of y is given by:
$y = 3 (10)

y = 30$ Answer:
the value of y when x = 10 is:
$y = 30$