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Alchen [17]
3 years ago
14

Wilma can mow a lawn in 60 minutes. Rocky can mow the same lawn in 40 minutes. How long does it take for both Wilma and Rocky to

mow the lawn if they are working together?
Mathematics
1 answer:
UNO [17]3 years ago
3 0
<h3>Answer:  24 minutes</h3>

===================================================

Explanation:

Let's say the lawn is 120 square feet. I picked 120 as it is the LCM (lowest common multiple) of 60 and 40.

Since Wilma can mow the lawn in 60 minutes, her rate is 120/60 = 2 sq ft per minute. In other words, each minute means she gets 2 more square feet mowed. Rocky can do the full job on his own in 40 minutes, so his rate is 120/40 = 3 sq ft per minute.

Their combined rate, if they worked together (without slowing each other down), would be the sum of the two rates. So we get 2+3 = 5 sq ft per minute as the combined rate. The total time it would take for this 120 sq ft lawn is 120/5 = 24 minutes.

--------------------------

Another approach

Wilma takes 60 minutes to do the full job, so her rate is 1/60 of a lawn per minute. Rocky's rate is 1/40 of a lawn per minute. Their combined rate is

1/60 + 1/40 = 2/120 + 3/120 = 5/120 = 1/24 of a lawn per minute

x = number of minutes

(combined rate)*(time) = number of jobs done

(1/24)*x = 1

x = 1*24

x = 24 is the time it takes if they worked together without getting in each other's way.

Effectively, we are solving the equation

1/A + 1/B = 1/C

with

A = time it takes Wilma to do the job on her own

B = time it takes Rocky to do the job on his own

C = time it takes the two working together to get the job done

The equation above is equivalent to C*(1/A + 1/B) = 1 or (1/A + 1/B)*C = 1.

So basically you find the value of 1/A + 1/B, then find the reciprocal of this to get the value of C.

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Which equation represents a line that passes through (4, 1/3) and has a slope of 3/4
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Y = mx + b
m = slope of the line
b= y-intercept

Since you are given the point (4,1/3), the y-value is 1/3.
So plug in the numbers and solve for b:
(1/3)= (3/4)*(4) + b

After you solve the equation for b, you should get -2 2/3 or -8/3

No rewrite the equation with the y-intercept, b.

y = (3/4 x) - (8/3)
5 0
3 years ago
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A boy wants to jump onto a carousel that is spinning at a rate of 14 revolutions per minute. If the carousel is 23 feet in diamt
nirvana33 [79]

Answer:

16.86 ft/s

Step-by-step explanation:

Given that

Speed of the carousel, s = 14 rpm

Distance from the carousel, d = 23 ft

To start with, we convert the given speed to revolution per second, so that

s = 14/60 rev/sec

To find the needed speed, we use the formula

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v = πnD, and we use this to find our needed velocity

v = 3.142 * 14/60 * 23

v = 72.266 * 14/60

v = 16.86 ft/s

Therefore the boy must run at a speed of 16.86 ft/s in order to be able to match the carousel and jump on it

6 0
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Maya spent her allowance on playing an arcade game a few times and riding the Ferris wheel more than once.
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Answer:

To write a two-variable equation, I would first need to know how much Maya’s allowance was. Then, I would need the cost of playing the arcade game and of riding the Ferris wheel. I could let the equation be cost of playing the arcade games plus cost of riding the Ferris wheel equals the total allowance. My variables would represent the number of times Maya played the arcade game and the number of times she rode the Ferris wheel. With this equation I could solve for how many times she rode the Ferris wheel given the number of times she played the arcade game.

Step-by-step explanation:

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Answer:

Step-by-step explanation:

5 0
2 years ago
What is the vertex of the graph of f(x) = x2 + 10x - 9? A) (-5, -34) B) (-5, -9) C) (5, -9) D) (5, 66)
sukhopar [10]

Answer:

A) (-5, -34)

Step-by-step explanation:

f(x) = x^2 + 10x - 9

We complete the square to get the equation in vertex form

Take the coefficient of the x term and divide by 2 then square it.  We add it and then subtract it not to change the value of the equation

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f(x) = x^2 +10x +25 -25 -9

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The term in parentheses simplified to (x+10/2) ^2

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This is in the form (x-h)^2 +k

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(-5,-34)

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