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HELP - MATH - Adding 3 ages up to equal 150

by Jesus
(Winchester)










































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?

The ages are 30, 47, and 10. The difference between my age and the oldest person is 17 years. I know it is x + (x+17)= 150. I know this is very simple but I am stuck and need some help understanding this.

Comments for HELP - MATH - Adding 3 ages up to equal 150

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Oct 08, 2012
Adding 3 ages
by: Staff


Answer:


Given the ages of three people:

10 years old, 30 years old, 47 years old



   • Write an equation:


Your equation is fine as long as you want the age of the middle person and the older person to add up to 150. This leaves out the younger person’s age.

Middle person’s age + Older person’s age = 150


x = middle person’s age


x + (x + 17) = 150


Solve for future ages
x + (x + 17) = 150


(x + x) + 17 = 150

2x + 17 = 150

2x + 17 - 17 = 150 - 17

2x + 0 = 150 - 17

2x = 150 - 17

2x = 133

2x/2 = 133/2

x*(2/2) = 133/2

x*(1) = 133/2

x = 133/2

x = 66.5


when the middle person’s age = 66.5

and the older person’s age = 66.5 + 17 = 83.5

then, the sum of the two ages will = 66.5 + 83.5 = 150



The equation which includes all three ages is:

Younger person’s age + Middle person’s age + Older person’s age = 150


x = middle person’s age


(x – 20) + x + (x + 17) = 150


Solve for future ages
(x – 20) + x + (x + 17) = 150


x – 20 + x + x + 17 = 150

x + x + x – 20 + 17 = 150

3x – 3 = 150

3x – 3 + 3 = 150 + 3

3x + 0 = 150 + 3

3x = 150 + 3

3x = 153

3x/3 = 153/3

x * (3/3) = 153/3

x * (1) = 153/3

x = 153/3

x = 51


when the middle person’s age = 51

and the older person’s age = 51 + 17 = 68

and the younger person’s age = 51 - 20 = 31

then, the sum of the three ages will = 31 + 51 + 68 = 150




Thanks for writing.

Staff
www.solving-math-problems.com



Oct 08, 2012
HELP - MATH - Adding 3 ages up to equal 150
by: Anonymous

Thank you for your assistance. I think that I understand x=51. Algebra is very confusing for me. I am trying to work the problem out to further understand; however, I need to know if there is anything that I should be looking at.

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