SOLUTION: one grandpa, one dad, one grandson. total age of these three is 140yrs. grandsons age in months is eqaul to the age of grandpa n years and grandsons age in days is eqaul to the age

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Question 696515: one grandpa, one dad, one grandson. total age of these three is 140yrs. grandsons age in months is eqaul to the age of grandpa n years and grandsons age in days is eqaul to the age of the dad in weeks. so what is the age of these three persons?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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one grandpa, one dad, one grandson. total age of these three is 140yrs.
grandsons age in months is equal to the age of grandpa n years,
and grandsons age in days is equal to the age of the dad in weeks.
so what is the age of these three persons?
:
let a = grandpa's age (yrs)
let b = dad's age
let c = grandson's age
:
Write an equation for each statement:
:
"one grandpa, one dad, one grandson. total age of these three is 140yrs."
a + b + c = 140
:
" grandsons age in months is eqaul to the age of grandpa n years"
a = 12c
:
"and grandsons age in days is eqaul to the age of the dad in weeks."
52b = 365c
b = 365%2F52c
:
Substitue for a and b in the 1st equation
12c + 365%2F52c + c = 140
13c + 365%2F52c = 140
mult by 52
52(13c) + 365c = 52(140)
676c + 365c = 7280
1041c = 7280
c = 7280/1041
c ~ 7 yrs old the grandson
How about grandpa?
12 * 7 = 84 yrs old is grandpa
and
Find Dad's age, using the total yrs equation
140 - 7 - 84 = 49 is dad's age
:
:
Check this
52(49) = 365(7)
divide both sides by 7
52*7 = 365
364 ~ 365, close enough?
:
so what is the age of these three persons? 84, 49, 7