hi.. i guess this is from the 700+ list...schreze wrote:Hi all, I just came across following question:
(1/5)^m (1/4)^18 = 1 / [2(10)^35]
Question: what is the value of m?
(A) 17
(B) 18
(C) 34
(D) 35
(E) 22
I have no idea how to do this and would appreciate your help.
here is how to do it..
1/ [ 2 x (10^35] = (1/5)^m x (1/2)^(18x2) = [1/(5^m)] x [1/ (2^36)]
take 5 x 2 = 10 and 5^a x 2^a = 10^a
so we have
1/ [ 2 x (10^35] = 1/ [ (5^m) x (2^35) x 2]
which suits the original eq.. so we proceed as
1/ [ 2 x (10^35] = 1/ [ 2 x (5 x 2)^35]
1/ [ 2 x (10^35] = 1/ [ 2 x (10^35]
so m has to be 35 in order for the eq to be true...
Answer is D
