Question 505650
Let
Present age of Ronald = r
Present age of Paula = p 
Present age of Mark = m

Paula is three times Mark's age
p=3m .........(1)
In two years means we have to add 2 in their present ages
p+2=r+2
then 
Paula will be twice the age Ronald will be at that time
p+2=2(r+2)
p+2=2r+4
p=2r+4-2
p=2r+2 ............(2)
Ronald is one year older than Mark means if we subtract to 1 from the Ronald's age then both Ronald and Mark will of equal age
m=r-1 ............(3)

Put the value of m from (3) to (1)
p=3m .........(1)
p=3(r-1)
p=3r-3 ............(4)
Put the value of p from (4) to (2)
p=2r+2 ............(2)
3r-3=2r+2
3r-2r=2+3
r=5
Put the value of r in (3)
m=r-1 ............(3)
m=5-1
m=4
Put the value of m in (1)
p=3m .........(1)
p=3(4)
p=12
Present age of Ronald = r = 5
Present age of Paula = p = 12 
Present age of Mark = m = 4