Ellen is 11 years older than Maja. Last year Ellen was twice as old as Maja. How old is Maja now?

Answer 1

E = M+11
Last year,
(E-1) = 2(M-1)

so, substitute:

(M+11-1) = 2(M-1)
M+10 = 2M-2
M = 12
so, E=23

Check: last year, 22 = 2*11