Question 1195973: Ed, his father, and his grandfather häve an average age of 53. One-half of his grandfather's
age, plus one-third of his father's age, plus one-fourth of Ed's age is 65. If 4 years ago, Ed's
grandfather was four times as old as Ed. then how old are they all now?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! x=Ed
y=father
z=grandfather
x+y+z=159 (total=n*average)
(1/2)z+(1/3)y+(1/4)x=65, and 6z+4y+3x=780
z-4=4(x-4), or z=4x-12
so
x+y+4x-12=159
5x+y=171
and
24x-72+4y+3x=780
27x+4y=852
from the other two variable equation multiplied by -4
-20x-4y=-684
so 7x=168
x=24 Ed
y=51 father
z=84 grandfather
that adds to 159
a quarter of Ed's is 6,a third of father's is 17 and half of grandfather's is 42. That sum is 65.
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