Question 322626
To solve this, you need to write it as two different equations and then set them equal to each other.
First we know that at a future age (we will call this F), Julia will be 10 more than 2 times her present age (we will call this P).  This can be written as:
F = (2*P) + 10
Secondly, we know at this future age she will be four times as old as she was four years ago (or present age minus 4):
F = 4* (P - 4)
Now since both equations equal F, we can set them equal to each other and solve.
(2*P)+10 = 4*(P-4) (multiply the right side out)
2P + 10 = 4P - 16  (now subtract 2P from both sides)
10 = 2P - 16   (now add 16 to both sides)
26 = 2P  (divide each side by 2)
13 = P
So Julia's present age is 13 years old.