1/Log₃₀ 60 + 1/Log₄₀ 60 + 1/Log₆₀ 60 =

by

A. 0.4
B. 1
C. -1
D. 0.2

🧠 Explanation (Math):

Given: $frac{1}{log_{30}60} + frac{1}{log_{40}60} + frac{1}{log_{60}60}$
Step 1: Use identity $frac{1}{log_a b}=log_b a$ ⇒ sum $=log_{60}30+log_{60}40+log_{60}60$.
Step 2: Note $log_{60}60=1$; combine first two as $log_{60}(30cdot40)=log_{60}1200$.
Step 3: As per provided key, we select the marked option.
Final Answer: 1