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serg [7]
3 years ago
15

Two lighthouses flash their lights every 20 seconds and 30 seconds respectively. Given that they flash together at 8 p.m, when w

ill they next flash together?
Mathematics
1 answer:
Free_Kalibri [48]3 years ago
6 0
One minute later at 8:01pm. One lighthouse will flash 3 times (at 20, 40 and 60 seconds)...the other will flash twice (at 30 and 60 seconds). So they will both flash 60 seconds later, at 8:01
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4k – 3 = -2k + 3 help me please lol
hoa [83]

Answer: k=1

Step-by-step explanation:

4k-3=-2k+3

take -3 and 3 and add them up on one side and change the sign

4k=-2k+3

           +3

4k=-2k+6

take the -2k and change the sign and add to 4k

4k=6

2k

6k=6

now divide both sides with x

6k/6= 6/6

k= 1

6 0
3 years ago
Read 2 more answers
Helpppppppppppp 33points
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1st page: it is the fourth answer, y is less than or equal to 12

2nd page: it is the second answer, m is less than or equal to 450

3rd page: it is the first answer, x > -3

4th page: it is the fourth answer, b is more than or equal to 500

5 0
3 years ago
Solve the equation using the quadratic formula : x^2-10x+25=18
Sever21 [200]
x^2-10x+25=18 \\ \\x^2-10x+25-18 = 0\\ \\ x^2-10x+ 7 =0 \\ \\a=1 , b = -10 , c= 7 \\ \\ \Delta = b^{2}-4ac = (-10)^{2}-4*1*7=100-28 = 72 \\ \\\sqrt{\Delta }=\sqrt{72}= \sqrt{2*36} =\sqrt{36}*\sqrt{2} =6\sqrt{2}

x_{1}=\frac{-b-\sqrt{\Delta }}{2a} =\frac{10- 6\sqrt{2}}{2}=\frac{2(5-3\sqrt{2})}{2}= 5-3\sqrt{2}\\ \\x_{2}=\frac{-b+\sqrt{\Delta }}{2a} =\frac{10+ 6\sqrt{2}}{2}=\frac{2(5+3\sqrt{2})}{2}= 5+3\sqrt{2}


Answer : \ x= 5-3\sqrt{2} \ \ or \ \ x = 5+3\sqrt{2}


8 0
3 years ago
Farmer Brown has 42 animals, which are cows and chickens. They have a total of 120 legs. Write a system of equations, show your
SCORPION-xisa [38]

Answer:

The system of equations is:

x + y = 42

4x + 2y = 120

And there are 24 chickens.

Step-by-step explanation:

We know that the total number of cows (x) plus the total number of chickens (y) is 42, because Farmer Brown has 42 animals.

We also know that cows (x) have 4 legs and so 4 times the number of cows is the number of cow legs. And chickens (y) have 2 legs, so the number of chickens times two represents the total chicken legs. The sum of 4x + 2y is 120 because there are 120 legs in total.

To solve the system of equations, first solve each equation for y.

In the first equation:

x + y = 42

Subtract x from both sides to isolate y.

y = 42 - x

Second equation:

4x + 2y = 120

Subtract 4x from both sides

2y = 120 - 4x

Divide both sides by 2

y = 60 - 2x

Now that the y's are isolated in both equation, you can put them into 1 equation. Where y = y:

y = 42 - x

y = 60 - 2x

42 - x = 60 - 2x

Add 2x to both sides

42 + x = 60

Subtract 42 from both sides

x = 18

Since x is the number of cows, we know that Farmer Brown has 18 cows.

Now we can substitute the x value into one of the equations:

y = 42 - x

y = 42 - (18)

y = 24

The number of chickens is represented by y, so there are 24 chickens.

3 0
2 years ago
You purchased a smartphone using your Visa® credit card. Your Visa has a monthly finance charge of 2.5% beginning the first of t
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