Question 5246
Let age of girl = x
Let age of brother = y
Let age of sister = z

x = y/2 --> 2x = y --> 2x - y = 0 --eqn1
x = z-2 --> z = x+2 --eqn2

x+y+z = 34 --eqn3


Sub eqn2 into 3, to give x+y+x+2 = 34
--> 2x+y = 32 --eqn4


So, we now have 2 equations to use: eqn1 and eqn4.

2x - y = 0
2x + y = 32


Subtracting these gives


-2y = -32
y = 16


so, as x=y/2 --> x=16/2 --> x=8
and z = x+2, so z = 10


So ages are: girl=8, brother=16 and sister=10


jon.