Question 761992
Mother = x
Petra = y
x + y = 47 ...1
Mother = 14 years older than twice as old as Petra
   x = 14 + 2y
Substitute in (1)
x + y = 47
(14 + 2y) + y = 47
      14 + 3y = 47
           3y = 47 - 14
           3y = 33
            y = 11
Petra = y = 11 years old
Mother = 14 + 2y = 36 years old
     36 + 11 = 47.
Hope this helps.
:-)