A can complete a piece of work in 15 days and B can complete the same work in 20 days. If they work together, in how many days will the work be completed?

60/7 days

8 days

10 days

50/7 days

APEDIA

NTPC Graduate Tier 1

2025 • 05 Jun, 2025 • Shift-2

A can complete a piece of work in 15 days and B can complete the same work in 20 days. If they work together, in how many days will the work be completed?

Correct Answer

60/7 days

Total Work Assumption: Determine the total units of work by finding the Least Common Multiple (LCM) of the given days (15 and 20). The LCM is 60 units.Individua......

💡 Analysis & Explanation

Total Work Assumption ▼

Determine the total units of work by finding the Least Common Multiple (LCM) of the given days (15 and 20). The LCM is 60 units.

Individual Efficiency ▼

A's efficiency is 60 / 15 = 4 units per day. B's efficiency is 60 / 20 = 3 units per day.

Combined Force ▼

Working simultaneously, their joint efficiency is 4 + 3 = 7 units per day.

Time Calculation ▼

The total time required is Total Work divided by Combined Efficiency, which translates to 60 / 7.

Conclusion ▼

The required time to finish the work is exactly 60/7 days.

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A can complete a piece of work in 15 days and B can complete the same work in 20 days. If they work together, in how many days will the work be completed?