SOLUTION: Mary is six years older than Jean. The sum of their ages is 20. How old is Mary

Question 404890: Mary is six years older than Jean. The sum of their ages is 20. How old is Mary
Answer by keksjr(7) (Show Source): You can put this solution on YOUR website!
Let Mary's age be: x , and Let Jean's age be y:
Since Mary is 6yrs older than Jean, therefore it implies that:
Mary's age = Jean's age + 6; x=y+6
And the sum of their ages being 20, that also implies that:
Mary's age + Jean's age = 20; x+y=20
Therefore lets find "y" that is Jean's age by substituting x=y+6 into x+y=20;
y+6+y=20
2y =20-6
2y =14
By Dividing through by 2; y =7
Then in finding how old Mary is: x=y+6
x=7+6
x=13
Therefore, Mary is 13yrs old

RELATED QUESTIONS
Andrew is three years older than Mary. if the sum of their ages total 27. How old is Mary (answered by Fombitz)

Jean is 7 years older than her brother bob and he is 3 years older than their sister... (answered by TimothyLamb)

Mary is 15 years older than her sister Jane. Six years ago Mary was 6 times as old as... (answered by JulietG)

Mary is 16 years older than David, David is 13 years younger than Charlie. If the sum of... (answered by greenestamps,MathTherapy)

Mary is 24 years older than her son John. The sum of their ages is 40. How old is John? (answered by rfer,Alan3354)

Mary is 6 years older than her sister kelly. The sum of their ages is 48. How old is... (answered by josgarithmetic)

George is 5 years older than Mary. The sum of their ages is 43 years. How old are George... (answered by algebrahouse.com)

Amos is four years older than Jean.In six year's time,the sum of their ages will be... (answered by Alan3354)

Mary is half as old as Tom. George is 3 years older than tom. The sum of Mary,tom,and... (answered by Maths68)