SOLUTION: james is twice as old as his friend peter. peter is 5 years older than alice right now. in 5 years, james will be three times as old as alice. how old is peter now?

Question 500013: james is twice as old as his friend peter. peter is 5 years older than alice right now. in 5 years, james will be three times as old as alice. how old is peter now?
Answer by Maths68(1474) (Show Source): You can put this solution on YOUR website!
Let
Present age of James = j
Present age of Peter = p
Present age of Alice = a
James is twice as old as his friend peter
j=2p ..........(1)
Peter is 5 years older than Alice
p=a+5..........(2)
In 5 years, James will be three times as old as Alice
j+5=3(a+5)
j+5=3a+15
j=3a+15-5
j=3a+10......(3)
Put the value of j from (1) in (3)
j=3a+10
2p=3a+10 .......(4)
Multiply (2) by -3 and add to (4)
p=a+5..........(2)
-3p=-3a-15
+2p=3a+10
----------------
-p=-5
Multiply by (-1) both sides of the above equation
(-1)-p=-5(-1)
p=5
Peter is 5 years old
Put the value of p in (1)
j=2p
j=2*5
j=10
James is 10 years old
Put the value of p in (2)
p=a+5
5=a+5
5-5=a
a=0
Alice is 0 years old !!!!!

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