Question 1121882: The average age of sadia ali and huma is 16years and that of ali huma and naila is 12 years if sadia is 13years old calculate naila age
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! let a = the age of sadia
let b = the age of ali
let c = the age of huma
let d = the age of naila
the average age of sadia, ali, and huma is 16 years old.
therefore a + b + c = 3 * 16 = 48
the average age of ali, huma, and naila is 12 years old.
therefore b + c + d = 3 * 12 = 36
sadia is 13 years old.
therefore a = 13
you have 2 equations that need to be solved simultaneously.
they are:
a + b + c = 48
b + c + d = 36
in the first equation, replace a with 13 to get 13 + b + c = 48 and solve for b + c to get b + c = 48 - 13 = 35
in the second equation, replace b + c with 35 to get 35 + d = 36 and solve for d to get d = 36 - 35 = 1
since d represents the age of naila, then naila must be 1 year old.
subtract 13 from both sides of each equation and combine like terms to get:
b + c = 48 - 13 = 35
b + d = 36 - 13 = 20
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