SOLUTION: The difference in ages between a boy and his younger brother is 6years.the younger brother is6 years older than his sister.the sum of ages if the younger brother and his sister is

Algebra.Com
Question 1078526: The difference in ages between a boy and his younger brother is 6years.the younger brother is6 years older than his sister.the sum of ages if the younger brother and his sister is 30.how old are the three children?

Found 3 solutions by ankor@dixie-net.com, MathTherapy, josgarithmetic:
Answer by ankor@dixie-net.com(22740)   (Show Source): You can put this solution on YOUR website!
let b = the boy's age
let y = the younger brother's age
let s = the sister's age
:
write an equation for each statement, arrange to have b and s in terms of y
;
The difference in ages between a boy and his younger brother is 6 years.
b - y = 6
b = y + 6
the younger brother is 6 years older than his sister.
y = s + 6
s = y - 6
the sum of ages if the younger brother and his sister is 30.
b + y + s = 30
replace b with (y+6), replace s with (y-6)
(y+6) + y + (y-6) = 30
combine like terms
3y = 30
y = 30/3
y = 10 yrs is younger bro's age
:
how old are the three children?
b = 10 + 6 = 16 yrs is the boy's age
and
s = 10 - 6 = 4 yrs is the sister's age
:
:
You can confirm this by finding the sum of the 3 ages

Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!

The difference in ages between a boy and his younger brother is 6years.the younger brother is6 years older than his sister.the sum of ages if the younger brother and his sister is 30.how old are the three children?
 

Answer by josgarithmetic(39617)   (Show Source): You can put this solution on YOUR website!
b, boy
y, younger brother
x, younger sister


-


Elimination Method on the system in y and x:
-


-


.
.

RELATED QUESTIONS

A boy is twice as old as his younger brother, and half as old as his older brother. In 22 (answered by josmiceli)
Andrew is 4 years older than his younger sister, Tina and he is 5 years younger than his... (answered by addingup)
a girl is 6years younger than her brother. The product of their ages is 135. Find their... (answered by Alan3354)
Marvin is 22 years older than his younger brother Raul. In 6 years, the sum of their ages (answered by VFBundy,mila nedic,MathTherapy)
Q The difference in age between a girl and her younger sister is 4 years. The younger... (answered by josgarithmetic)
Steve is 7 years younger than his brother Richard. If the sum of their ages is 37 years,... (answered by josgarithmetic)
the difference between a girl and her younger sister is 4 years. the younger sister in... (answered by josmiceli)
A boy is half as old as his sister and two years younger than this brother. The sum of... (answered by rfer)
harry is x years old, his brother is two times older and his sister is 5 years younger... (answered by ankor@dixie-net.com)