Let beth's age be x, and john's age be y.
then from the first sentence, we derive that beth is 16 yrs younger than john
x + 16 =y
from second sentence, we have that
then we get the following equations
x+16=y ..........(eqn 1)
y+10=2x ........(eqn 2)
substituting y+x+16 from eqn 1 into equation 2, gives
which gives x=26
then y=x +16...
beth is 26 years and john is 42 years