SOLUTION: my uncles weight is three times of my nephews weight.My aunts weight is 3/4 of my uncles weight. If the sum of their weight is 180kg. What is their weight?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: my uncles weight is three times of my nephews weight.My aunts weight is 3/4 of my uncles weight. If the sum of their weight is 180kg. What is their weight?      Log On


   

Question 1073544: my uncles weight is three times of my nephews weight.My aunts weight is 3/4 of my uncles weight. If the sum of their weight is 180kg. What is their weight?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
let u = uncle's weight
let n = nephew's weight
let a = aunt's weight
:
my uncles weight is three times of my nephews weight.
u = 3n
divide both sides by 3 and you have
n = 1%2F3%29u
My aunts weight is 3/4 of my uncles weight.
a = 3%2F4u
If the sum of their weight is 180kg.
u + n + a = 180
Replace n and a
u + 1%2F3u + 3%2F4u = 180
Get rid of the fractions, multiply the equation by 12 and you have
12u + 4u + 3(3) = 12(180)
12u + 4u + 9u = 2160
25u = 2160
u = 2160/25
u = 86.4 is the uncles age
then
1%2F3*86.4 = 28.8 is nephew's age
and
3%2F4 * 86.4 = 64.8 is aunt's age
:
We should have integer solutions here, see if they add up to 180
86.4
28.8
64.8
-----
180