Question 674350: In years, how old was the older person when you were born?
28 (Myself)
10 (brother)
50 (mother)
Write an equation that models how old in years each of you will be, when your ages add up to 150 years old. For example, if x = your age and the eldest person was a year older than you, you would write their age as x + 1. Then the equation would be: x + (x+1) = 150.
Explain the reasoning which helped you develop your equation.
Solve for your future ages. Are your answers reasonable, do they add up to 150?
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! let x = your age now.
your brother's age is x - 18 now because x - 18 = 10
your mother's age is x + 22 now because x + 22 = 50
you want to find out how old each of you will be when the sum of your ages is 150.
the equation would be x + x - 18 + x + 22 = 150
combine like terms to get 3x + 4 = 150
subtract 4 from both sides of the equation to get 3x = 146
divide both sides of the equation by 3 to get x = 146/3
when the sum of your ages is 150, you will be 146/3 years old, your brother will be 146/3 - 18 years old, and your mother will be 146/3 + 22 years old.
in decimal terms, that means:
you will be 48.67 years old
your brother will be 30.67 years old
your mother will be 70.67 years old
add them up and they equal 150.01 which is the same as 150 if we ignore the rounding error.
the older person is 50 years old.
you are 28.
when you were born, the older person was 28 years younger which makes the older person 50 - 28 = 22.
your mother was 22 when you were born.
your age is now x.
your mother's age is x + 22.
when x is equal to 0, x + 22 is equal to 22 so it check out.
the reasoning behind this is that we are taking your age as the base and everything else is relative to that base.
the difference between their age and your is constant which allows the equatins to work regardless of your age.
|
|
|
