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Justin is 10 years older than Maggie. Four years ago, Justin was three times as old as Maggie. Find Justin’s age now.

Respuesta :

Solution:

Note that:

  • J = 10 + M
  • J - 4 = 3(M - 4)

Finding Maggie's age:

  • J - 4 = 3(M - 4)
  • => J - 4 = 3M - 12
  • => M + 10 - 4 = 3M - 12
  • => M + 6 = 3M - 12
  • => 12 + 6 = 3M - M
  • => 18 = 2M
  • => M = 9

Finding Justin's age:

  • J = 10 + M
  • => J = 10 + 9
  • => J = 19

Let Justin's age be x

Let Maggie's age be y

ATQ,

[tex] \pmb {x = 10 + y} \\ \pmb{x-4=3(y-4)}[/tex]

Solve using the substitution method!!

  • In this way the equation will be easier to solve because we will get the value of both x and y together...

[tex] \pmb{10 + y - 4 = 3(y - 4)}[/tex]

[tex] \sf 6 + y = 3y - 12[/tex]

[tex] \sf y - 3y =- 12 - 6[/tex]

[tex] \sf - 2y =- 18 [/tex]

[tex] \sf y =9[/tex]

Substitute the value of y into the first equation

[tex] \pmb{x= 10 + y} \\ \pmb{x = 10 + 9} \\ \pmb{x = 19}[/tex]

Thus, Maggie's age is 9 and Justin's age is 19...~