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Simon has three numbers. The third number is four more than the first number, and the second number is five more than three times the third number. The sum of the three numbers is sixteen. What is the first number?

 Dec 15, 2019
 #1
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Let the numbers  be  X, Y  and Z  in that order

 

And we have that

 

X + 4  = Z    ⇒  Z  - 4  = X        (1)

Y = 3Z + 5      (2)

X + Y  + Z  = 16      (3)

 

 

Sub (1)  and (2) into (3)   and we have that

 

[Z - 4] + [3Z + 5]  + Z  = 16   simplify

 

5Z + 1  =16       subtract 1 from each side

 

5Z  = 15       divide both sides by 5

 

Z  =3

 

So....the first number, X  = Z - 4   = 3  - 4   = -1

 

 

cool cool cool

 Dec 15, 2019

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