Question 921015
 
let m = his age
let s = son's age
let g = granddaughter's age
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write an equation for each statement
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My grand daughter is about as many days as my son is in weeks,
s = 7g
 and my grand daughter is as many months as I am in years.
m = 12g
 My grand daughter, my son and I together are 120 years.
g + s + m = 120
replace s with 7g; replace m with 12g
g + 7g + 12g = 120
20g = 120
g = 120/20
g = 6 yrs is granddaughter's age
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 Can you tell me my age in years
m = 12 * 6
m = 72 is your age
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Check this; s = 7*6 = 42 is son's age
6 + 42 + 72 = 120