Question257

x, y, z are real numbers greater than 1 and w is a positive real number. If log_xw = 24, log_yw = 40 and log_xyzw = 12, find log_zw

a) 120

b) 60

c) 4

d) None of these

Ans: b) 60

w = x²⁴ = y⁴⁰ = x¹²y¹²z¹², so w¹⁰ = x¹²⁰y¹²⁰z¹²⁰ = w⁵w³z¹²⁰, so w = z⁶⁰