Difficulty: Medium
Correct Answer: 60 days
Explanation:
Problem restatement
We know the joint time for (A + B), a head start by A, and the finishing time by B alone. Find B's solo time.
Given data
Concept/Approach
Express a = 1/30 − b and substitute into the remainder equation to solve for b.
Step-by-step calculation
44b = 1 − 16(1/30 − b) = 1 − 16/30 + 16b = 1 − 8/15 + 16b = 7/15 + 16b 44b − 16b = 7/15 → 28b = 7/15 → b = 1/60 Therefore, B's time = 1 ÷ b = 60 days
Verification
Then a = 1/30 − 1/60 = 1/60; A's 16 days produce 16/60 = 4/15 of the job; remainder 11/15 finished by B in 44 days → 44 × (1/60) = 11/15 (consistent).
Common pitfalls
Final Answer
60 days
Discussion & Comments