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3 years ago

7

One person can do a certain job in twenty-one minutes, and another person can do the same job in twenty-eight minutes. How many

minutes will it take them to do the job together?
6 min
12 min
24 min

2 answers:

jenyasd209 [6]3 years ago

7 0

$\dfrac{1}{21}+\dfrac{1}{28}=\dfrac{1}{x}\\
\dfrac{4}{84}+\dfrac{3}{84}=\dfrac{1}{x}\\
\dfrac{7}{84}=\dfrac{1}{x}\\
7x=84\\
x=12$

Zigmanuir [339]3 years ago

5 0

Answer:

12 minutes

Step-by-step explanation:

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Given: ABCD trapezoid<br> BC=1.2m, AD=1.8m<br> AB=1.5m, CD=1.2m<br> AB∩CD=K<br> Find: BK and CK

stepladder [879]

Answer:

The value of BK is 3m and the value of CK is 2.4m.

Step-by-step explanation:

Given information: ABCD trapezoid

, BC=1.2m, AD=1.8m

, AB=1.5m, CD=1.2m

, AB∩CD=K.

Using the given information draw a figure.

Two sides of a trapezoid are parallel.

Since AB∩CD=K, therefore AB and CD are not parallel, because parallel line never intersect.

$AD\parallelBC$

$\angle KBC=\angle KAD$ (Corresponding angles)

$\angle KCB=\angle KDA$ (Corresponding angles)

By AA rule of similarity

$\triangle KBC\sim \triangle KAD$

Corresponding sides of similar triangles are proportional.

$\frac{KB}{KA}=\frac{KC}{KD}=\frac{BC}{AD}$

$\frac{x}{x+1.5}=\frac{y}{y+1.2}=\frac{1.2}{1.8}$

$\frac{x}{x+1.5}=\frac{1.2}{1.8}$

$\frac{x}{x+1.5}=\frac{2}{3}$

$3x=2x+3$

$x=3$

The length of BK is 3 m.

$\frac{y}{y+1.2}=\frac{1.2}{1.8}$

$\frac{y}{y+1.2}=\frac{2}{3}$

$3y=2y+2.4$

$y=2.4$

The length of CK is 2.4 m.

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3 years ago

Read 2 more answers

In a toy store, the ratio of the number of dolls to the number of teddy bears is . If the store has 240 dolls, how many teddy

forsale [732]

Answer:

<u>So, the way a ratio works is </u><u>"for every 1 of this, we have 4 of this"</u><u> for example. (the ratio I just described would be 1:4.) </u>

<u />

I believe I've seen this question before. If the ratio of dolls to teddy bears is 9:3 then for every 9 dolls you have 3 teddy bears.

So, since we have 240 dolls and a 9:3 ratio to teddy bears, all we have to do is take how many dolls we have (240) and divide it by 3 to see how many teddy bears we have.

So:

240 ÷ 3 = 80

If your ratio is 9:3, then 80 is your answer.

<u>Hope this helps and have a nice day!</u>

<u></u>

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3 years ago

Mr. Shively’s TV cabinet is 30 inches tall and 40 inches wide. Best Buy is selling 50 inch, 55 inch, 60 inch, and 65 inch TVs. O

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Answer:

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Step-by-step explanation:

Using Pythagorean theorem the TV cabinet has a diagonal of :

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Answer:

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Step-by-step explanation:

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Upon rounding our answer to nearest cent we will get,

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