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Zolol [24]
3 years ago
7

Two lighthouses flash their lights every 20 and 30 seconds respectively. given that they flash together at 8 p.m., at what time

will they next flash together? answer:
Mathematics
1 answer:
VikaD [51]3 years ago
6 0
Do you remember when you were learning about
Least Common Multiple (LCM) ?  And you were
wondering what on Earth you would ever need it for ?

THIS IS IT !

The amount of time after 8 PM when the lights will flash
together again is the LCM of 20 seconds and 30 seconds.
Do you remember how to find it ?

... When 20 is prime-factored, you have  2 · 2 · 5 .

... When 30 is prime-factored, you have  2 · 3 · 5 .

... So the Least Common Multiple of 20 and 30 is  2 · 2 · 3 · 5  =  60 .

The lighthouses will flash together again in 60 seconds after 8 PM.
That'll be  8:01 PM.  
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Solve by substitution or elimination<br> 4X – 3y = 7<br> 4x + y = 11
Simora [160]

Answer:

(5/2 , 1)

Step-by-step explanation:

4X – 3y = 7

4x + y = 11

———————

Multiply a -1 to the bottom equation to get the 4x as a negative so it cancels out.

4x - 3y = 7

-4x - y = -11

——————

-4y = -4

Divide by -4

y = 1

Substitute the value of y into one of the equations and solve

4x - 3(1) = 7

4x -3 = 7

4x = 10

Divide by 4

X = 10/4

Simplify by dividing by 2

x = 5/2

Therefore the answer is (5/2, 1 )

8 0
3 years ago
Which of the following points is a vertex for the image produced by a dilation about the origin with a scale factor of 1/2?
MA_775_DIABLO [31]

Answer:

A (0,3)

Step-by-step explanation:

The given trapezoid has vertices:

(0,6), (7,12), (7,9) and (0,12).

We want to choose from the given options, a point that is a vertex for the image produced by a dilation about the origin with a scale factor of 1/2.

Note that the mapping for such a dilation is:

(x,y)\to( \frac{1}{2} x, \frac{1}{2} y)

This implies that:

(0,6)\to(0,3)

(7,12)\to(3.5,6)

(7,9)\to(3.5,4.5)

(0,12)\to(0,6)

Therefore correct choice is (0,3)

8 0
3 years ago
Kara used the linear model y=45,000+ 0.05x to predict her total salary from achieving total sales of x.
hoa [83]

Answer:

45,000 is the starting salary with zero sales

.05 is the amount multiplied by the number of sales that is added to her salary

For each sale we add .05 to her salary

Step-by-step explanation:

y = 45,000 +.05x

Rewriting as

y = .05x +45,000

This is in slope intercept form ( y=mx+b) where m is the slope and b is the y intercept

.05 is the slope and 45,000 is the y intercept

45,000 is the starting salary with zero sales

.05 is the amount multiplied by the number of sales that is added to her salary

For each sale we add .05 to her salary

6 0
3 years ago
Roberto debe leer un libro que contiene 340 páginas en cuatro días para lo cual planea la siguiente distribución de lectura: el
Murrr4er [49]

Answer: le quedan leer 295 páginas

Step-by-step explanation:

6 0
2 years ago
Find the value of 1/2 divide by 1/3
Hunter-Best [27]

Answer:

1.5

Step-by-step explanation:

its 1.5 not 1/5

5 0
3 years ago
Read 2 more answers
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