Question 150401
1. Erwin is 5 times older than john and John is twice as old as his sister, Alice.


Erwin=5j
John=j; 2a
Alice=a; 1/2j


Use j, since all of the people can be expressed in terms of j.
In 2 years time, the sum of their ages will be 58.

5j+2+j+2+1/2j+2=58


Combine like terms
6.5j+6=58


Subtract 6
6.5j=52


Divide by 6.5
j=8


Erwin=5(8)
John=(8)
Alice=1/2(8)


5(8)+(8)+1/2(8)+6=58
40+8+4+6=58


Erwin=40
*John=8*
Alice=4
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2. John is twice as old as his friend peter. Peter is 5 years older than Alice.


John=2p
Peter=p; a+5
Alice=p-5


Use p as the variable.
In 5 years, John will be three times as old as Alice.
2p+5=3(p-5+5)


Simplify
2p+5=3p


Subtract 2p from both sides
5=p


John=2(5)
Peter=(5)
Alice=(5)-5


John=10
*Peter=5*
Alice=0
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3. Reggie is 5 years older than Lani.


Reggie=L+5
Lani=L


Five years ago, the sum of their ages is 25.
(L+5)-5+(L)-5=25


L+L-5=25
2L-5=25
2L=30
L=15


Reggie=(15)+5
Lani=(15)


Reggie=20
Lani=15