SOLUTION: Debra is three more than nine times as old as John. Kevin is half as old as Debra. Sara is 5 years old, which is one-third as old as Kevin. Find John's age.
Question 498716: Debra is three more than nine times as old as John. Kevin is half as old as Debra. Sara is 5 years old, which is one-third as old as Kevin. Find John's age. Answer by Maths68(1474) (Show Source):
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Current age of Debra=d
Current age of John=j
Current age of Kevin=k
Current age of Sara=s=5
Debra is three more than nine times as old as John
3+9j=d………….(1)
Kevin is half as old as Debra
d/2=k…………..(2)
Sara is 5 years old, which is one-third as old as Kevin
1/3(k)=s…………(3)
1/3(k)=5
k=5*3
k=15
Put the value of k in (2)
d/2=k
d/2=15
d=15*2
d=30
Put the value of d in (1)
3+9j=d
3+9j=30
9j=30-3
9j=27
9j/9=27/9
j=3
John is 3 years old
