1) If 2x=3y=6−z, then (1x+1y+1z) is equal to? A) 0 B) 1 C) 3/2 D) -1/2 Answer: Option AExplanation:Let 2x=3y=6−z=k ⇔2=k1x, ⇔3=k1y and ⇔6=k−1z. Now 2×3=6 ⇔k1x×k1y=k−1z ⇔k(1x+1y)=k−1z ∴1x+1y=−1z ⇔1x+1y+1z=0