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Leviafan [203]
3 years ago
9

The Lees have 3 children. The oldest is twice as old as the youngest. The middle is 5 years older than the youngest. If the sum

of the age is 57, how old is each child?
Mathematics
2 answers:
lesya692 [45]3 years ago
6 0

Answer:

77

Step-by-step explanation:

valina [46]3 years ago
4 0
Oldest = 2 times Youngest -> O = 2*Y
Middle = Youngest + 5 -> M = Y+5
All of them together is 57 -> O + M + Y = 57

So you have these three equations:
(1) O = 2*Y
(2) M = Y+5
(3) O + M + Y = 57

Now you want to reduce the number of variables. You can change the second equation to be Y = M-5 and then plug in "M-5" wherever there is currently a Y:

(4) O = 2*(M-5) = 2*M - 10
(5) O + M + (M-5) = 57 
    which becomes O + 2M = 62

Then you plug in the "O" equation (4) into (5) which gives you
(2M-10) + 2M = 62 which reduces to 4M = 72.

So now I know M is 18. 
I can now plug that into my other equations:
(4) O = 2*18 - 10 which means O = 26.
Now I plug that into (1) from the top:
26 = 2*Y which becomes 13 = Y

So now I have O, Y, and M
Oldest is 26
Middle is 18
Youngest is 13

Reading the sentence again, you can see that this makes sense. 


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Answer:

7

Step-by-step explanation:

200/25.50

7.8

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2 years ago
Prove that one of every three consecutive positive integer is divisible by 3
Inessa05 [86]
Hello : 
all n in N ; n(n+1)(n+2) = 3a    a in  N  or : <span>≡ 0 (mod 3)
1 ) n </span><span>≡ 0 ( mod 3)...(1)

     n+1 </span>≡ 1 ( mod 3)...(2)
      n+2 ≡ 2 ( mod 3)...(3)
by (1), (2), (3)  : n(n+1)(n+2) ≡ 0×1×2   ( mod 3)   : ≡ 0 (mod 3)
2) n ≡ 1 ( mod 3)...(1)

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5 0
3 years ago
9. A simple interest loan with a principal of
8090 [49]

Answer:

437.50

Step-by-step explanation:

Okay so you need to give him 5000 but now its 5875 cuz you waited so just do 875÷2

3 0
2 years ago
Which table represents a linear function?
zloy xaker [14]

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Step-by-step explanation:

Each time x increases by 1, y increases by 2. Since there is a constant increase in y for each time x increases by 1, the table represents a linear function.

4 0
2 years ago
3
Zanzabum

A pergunta não está bem formatada. No entanto, pelo que parece óbvio

Responda:

3 horas

Explicação passo a passo:

Fração de hora gasta por sessão = 3/4 horas por sessão

Se o exercício for feito apenas aos domingos

Número de domingos por mês = 4

Portanto, número de sessões = 4

Fração de horas por sessão * Número de sessões

3/4 * 4 = 3 horas

Portanto, 3 horas são dedicadas ao exercício por mês

6 0
2 years ago
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