Question 491644: Bob's dad is 27 years older than Bob. The sum of their ages 5 years ago was 45 years. How old is Bob now?
Answer by Maths68(1474)   (Show Source):
You can put this solution on YOUR website! Let
d=Current age of dad
b=Current age of Bob
Bob's dad is 27 years older than Bob so if we add 27 years to the Bob’s age both will be of same age
d=b+27………(1)
5 years ago means subtract 5 from both the ages
Dad age 5 years ago = d-5
Bob age 5 years ago = b-5
The sum of their ages 5 years ago was 45 years means
(d-5)+(b-5)=45
d-5+b-5=45
d+b-10=45
d+b=45+10
d+b=55
b=55-d…………………(2)
Put the value of b in (1), we have
d=b+27………(1)
d=55-d+27
d+d=55+27
2d=82
Divide by 2 both sides
2d/2=82/2
d=41
put the value of d in (2), we have
b=55-d…………………(2)
b=55-41
b=14
Bob is 14 and Daddy is 41 years old
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