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john is twice as old as his friend peter.peter is 5 years older than alice. in 5 years. john will be 3 times as old as alice. how old is peter now?

 Feb 12, 2019
 #1
avatar+102461 
+2

john is twice as old as his friend peter.peter is 5 years older than alice. In 5 years, john will be 3 times as old as alice. how old is peter now?

 

J=2P

P=A+5

J+5=3(A+5)

 

Find P

 

J=2P=2(A+5) 

so

2(A+5) +5=3(A+5)

5=A+5

 

A=0

P=5

J=10

 

check

john is twice as old as Peter.    True

Peter is 5 years older than Alice    True

In 5 years john will be 15 and Alice will be 5. John will be 3 times older.   True

 

Peter is 5 now.

 Feb 12, 2019
 #2
avatar+18458 
+2

I got the same answer as Melody, then I wondered about the wording of the question when I found Alice = 0.

So I wondered if it was SUPPOSED to say THIS:

 

john is twice as old as his friend peter.peter is 5 years older than alice. in 5 years. john will be 3 times as old as alice is NOW. how old is peter now?

 

J=2P             (1)

P=A+5          (2)

J+5=3A         (3)

 

1 in to 3       2P +5 = 3A    Then sub 2 into the equation

                   2(A+5) +5 = 3A

                   2A + 15 = 3A

                     15 = A

 

Then P = A+5 = 20      and J = 2P=40         This is NOT what the question asked....this is the question I posted above....

 Feb 12, 2019
 #3
avatar+101871 
+1

Let Alice's age = A

Let Peter's age = A + 5

Let John's age = 2(A + 5)

 

And we know that

 

Jonh's Age + 5 years =  3times Alice's age  .....so.....

 

2(A + 5) + 5 = 3A

2A + 15 = 3A

15 = A     =   Alice's age

 

Peter = A + 5  =  20

 

John is   2(20) =  40

 

And in 5 years.....John will be 3 times Alice's age 

 

 

cool cool cool

 Feb 12, 2019

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