Jennifer is twice as old as laurel, who is 4 years younger than nana. If nana is two years younger than Jennifer what is nana’s age in years?
Jennifer's age = J
Laurel's age = L
Nana's age = N
Jennifer is twice as old as Laurel: J = 2·L
Laurel is four years younger than Nana: L = N - 4
Nana is two years younger than Jennifer: N = J - 2
Combining J = 2·L and L = N - 4 ---> J = 2·(N - 4)
Combining J = 2·(N - 4) and N = J - 2 ---> N = 2·(N - 4) - 2
---> N = 2N - 8 - 2
---> N = 2N - 10
---> 10 = N