Question 636356
Let 
Present age of Julies = j years old
Present age of Father = f years old


the sum of julies age and her fathers age is 58
j+f=58
j=58-f.............(1)
julies father is 10 years younger than triple Julie's age
3j=f-10............(2)
Put the value of j from (1) to (2)
3j=f-10
3(58-f)=f-10
174-3f=f-10
-3f-f=-10-174
-4f=-164
-4f/-4=-164/-4
f=41
Put the value of f in (1)
j=58-f.............(1)
j=58-41
j=17




Present age of Julies = j = 17 years old
Present age of Father = f = 41 years old