sandy wrote:
Louise is three times as old as Mary. Mary is twice as old as Natalie. If Louise is L years old, what is the average (arithmetic mean) age of the three women, in terms of L?
(A) L3
(B) L2
(C) 2L3
(D) L4
(E) L6
L = 3M ; M = 2N ; L = L all of are in terms of their given value.
Now L = 3M = 3* 2N(where M=2N) = 6N So, L=6N;
Therefore, L=6N ; M=2N ; L=N(lets assume L=N); and there sum of 6N+2N+N=9N
Now we need to divide by 3 as they want AVERAGE So 9N/3=3N
BUT we know that L=6N/3N = L/2