A person travels from A to B at 40 km/h and returns from B to A at 60 km/h. His average speed for the whole journey is: MCQ with Answer and Explanation

Explanation:
Yule's Q = [(AB)(αβ) - (Aβ)(αB)] / [(AB)(αβ) + (Aβ)(αB)]; if the denominator is zero (all cells zero or impossible configuration), Q is undefined, though this rarely occurs in real data.

Explanation:
PNMR = (stillbirths + early neonatal deaths) / (live births + stillbirths) × 1000.

Explanation:
Agreement can be both truth or both lie. P(both truth)=0.6×0.7=0.42; both lie=0.4×0.3=0.12. Total agreement=0.54. Probability truth given agreement = 0.42/0.54 ≈ 0.7778.