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andreev551 [17]
3 years ago
15

Bob and sarah need to paint a fence. bob can paint the fence in 4 hours and sarah can paint the fence in 2.5 hours. if they work

together, how long will it take them to paint the fence?
Mathematics
1 answer:
zysi [14]3 years ago
7 0
If Bob can paint the fence in 4 hours, then in 1 hour he gets 1/4 of the fence painted.  If Sarah can paint the fence in 2.5 hours, then she gets 2/5 of the fence painted in one hour (1/2.5 = 2/5).  We add those amounts together and set them equal to 1/x, x being the the total time it will take them to paint the whole fence.  1/4 + 2/5 = 1/x.  Find a common denominator first, then add the left side together.  5/20 + 8/20 = 1/x.  13/20 = 1/x.  Cross-multiply to get 13x = 20 and x = 1.54 hours, just a bit over an hour and a half.
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A polynomial P has zeros when x=0, x=-1/6 and x=-3 Whats could be the equation p?
erma4kov [3.2K]

Answer:

P(x) = x^{3} + \frac{19}{6} x^{2} + \frac{1}{2} x

Step-by-step explanation:

x(x + 1/6)(x + 3) = P

x(x^{2} + 3x + 1/6(x) + 1/2) = P

x (x^{2} + 19/6(x) + 1/2) = P

x^{3} + \frac{19}{6} x^{2} + \frac{1}{2} x = P(x)

4 0
2 years ago
Help! What is the average rate of change of f(x)=x^2+3x+6 over the interval -3 less-than-or-equal-to x less-than-or-equal-to 3?
Makovka662 [10]

Answer:

The average rate of change of the function over the interval is 5.

Step-by-step explanation:

Average rate of change of a function:

The average rate of change of a function f(x) over an interval [a,b] is given by:

A = \frac{f(b)-f(a)}{b-a}

Interval -3 less-than-or-equal-to x less-than-or-equal-to 3

This means that a = -3, b = 3

f(x) = x^2 + 3x + 6

So

f(b) = f(3) = (3)^2 + 3(3) + 6 = 9 + 9 + 6 = 24

f(a) = f(-3) = (-3)^2 + 3(-3) + 6 = 9 - 9 + 6 = 6

Average rate of change

A = \frac{f(b)-f(a)}{b-a} = \frac{24+6}{3-(-3)} = \frac{30}{6} = 5

The average rate of change of the function over the interval is 5.

8 0
3 years ago
Can someone explain (with steps) how to rationalize the following expression?
insens350 [35]
F(x)=(-2/((x+y-2)^(1/2))-(x+y+2)^(1/2)
the only irrational part of this expression is the (x+y-2)^(1/2) in the denominator, so, to rationalize this, you multiply the numerator and denominator by the denominator, as well as the other parts of the expression
also, you must multiply the -sqrt(x+y+2) by sqrt(x+y-2)/sqrt(x+y-2) to form a common denominator
(-2)/(x+y-2)^(1/2)-(x+y+2)^(1/2)(x+y-2)^(1/2)/(x+y-2)^(1/2)
(common denominator)
(-2-(x^2+xy+2x+xy+y^2+2y-2x-2y-4))/(x+y-2)^(1/2)
(FOIL)
(-2-x^2-y^2-2xy+4)/(x+y-2)^(1/2)
(Distribute negative)
(-x^2-y^2-2xy+2)/(x+y-2)^(1/2)
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(-x^2-y^2-2xy+2)(x+y-2)^(1/2)/(x+y-2)^(1/2)(x+y-2)^(1/2)
(Rationalize denominator by multiplying both top and bottom by sqrt)
(-x^2-y^2-2xy+2)((x+y-2)^(1/2))/(x+y-2)
(The function is now rational)
=(-x^2-y^2-2xy+2)(sqrt(x+y-2))/(x+y-2)
6 0
3 years ago
How many 1/4 cup servings are in 4 cups of oatmeal ?
Wewaii [24]
4 1/4 cup servings
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5 0
3 years ago
Read 2 more answers
AaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaA
Ganezh [65]

Answer:

the answer is

B.Plate

i hope this helps ~_~

4 0
3 years ago
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