Difficulty: Medium
Correct Answer: Any two of the three
Explanation:
Introduction / Context:We must identify which statements suffice to find the time taken by 10 women to finish one unit of work. Treat rates linearly (work/day).
Given Data / Assumptions:
Concept / Approach:We need 10W (the collective women’s rate) to get time = 1 / (10W). Any two independent equations among I–III determine M and W (or directly 10W).
Step-by-Step Solution:
I + II ⇒ 10M = 1/6; 10M + 10W = 7/24 ⇒ 10W = 7/24 − 1/6 = 7/24 − 4/24 = 3/24 = 1/8 ⇒ time = 8 days.I + III ⇒ 10M = 1/6 ⇒ work by 10M in 3 days = 1/2; hence 10W * 4 = 1/2 ⇒ 10W = 1/8 ⇒ time = 8 days.II + III ⇒ Solve two equations for M and W; yields the same 10W = 1/8 ⇒ time = 8 days.Verification / Alternative check:Each pair independently leads to 8 days for 10 women.
Why Other Options Are Wrong:
Common Pitfalls:Adding “days” instead of rates; forgetting to convert 3 3/7 to 24/7 properly.
Final Answer:Any two of the three
Discussion & Comments