Question 521132: Renee is 5 years older than Paulo, she is also 7 years older than Peter. The sum of their ages is 21 ,How old is each person.
Answer by mamiya(56)   (Show Source):
You can put this solution on YOUR website! let r be Renee's age, p be Paulo's age and t be Peter's age.
the sum of their age is 21, means r + p + t=21
Renee is five years older than Paulo, so r= p + 5
Renee is seven years older than Peter, so r= t + 7
r=r, so p + 5= t+ 7
p - t = 2 (1)
we know, r + p +t= 21
since r= p+5, so p+5 + p + t=21
2p + t = 21-5 =16 (2)
by adding up the two equations (1) and (2)
we have, (p-t) + (2p + t)= 2 + 16
3p=18
so p=6
r= p + 5 = 6 + 5= 11
t + 7= r, so t= r - 7
=11-7
=4
so, Renee is 11 years old, Peter is 6 years old and Peter is 4 years old.
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