Respuesta :

Answer:

30

Step-by-step explanation:

to understand the steps

you need to know about:

  • system of linear equation
  • word problems
  • PEMDAS

first step

let's create the equation word problem

my mother's current age is four times the sum of the ages of my two sisters. After 5 years, my mother's age will be double the sum of the ages of my two sisters. What is the current age of my mother? (imaginary problem)

let's solve

let my mother's and sister's age be x and y respectively

according to the first condition,x=4y....(I)

according to the 2nd condition,x+5=2(y+5×2).....(ii)

so the system of linear equations is

x=4y

x+5=2(y+5×2)

gets from the second equation

x+5=2(y+10)

x+5=2y+20

4y+5=2y+20 (as x=4y)

2y=15

y=7.5

so the age of mother is

x=4.(7.5)

x=30

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