Question 1

If A's work efficiency is twice that of B, and A can complete a task in 10 days, how many days will B take to complete the same task?

Accepted Answer

Step 1: A's efficiency = 1/10 work per day. Step 2: A's efficiency is twice B's efficiency, so B's efficiency = (1/10) ÷ 2 = 1/20 work per day. Step 3: Time for B = 1 ÷ (1/20) = 20 days.

Question 2

A's efficiency is twice that of B. If A alone can complete a job in 9 days, how many days will B take to complete the same job?

Accepted Answer

Step 1: A's efficiency = 1/9 (work per day). Step 2: Since A's efficiency is twice B's efficiency, B's efficiency = (1/9) ÷ 2 = 1/18. Step 3: Time for B = 1 ÷ (1/18) = 18 days. Therefore, answer is 18 days.

Question 3

A can do 1/3 of a work in 5 days. How many days will A take to complete the entire work?

Accepted Answer

Step 1: A completes 1/3 of work in 5 days. Step 2: To complete the entire work (3/3), A needs 3 times as many days. Step 3: Total days = 5 × 3 = 15 days.

Question 4

B takes 50% more time than A to complete a task. If A completes the task in 8 days, how many days will B take?

Accepted Answer

Step 1: A completes the task in 8 days. Step 2: B takes 50% more time than A. Step 3: B's time = 8 + (50% of 8) = 8 + 4 = 12 days.

Question 5

A's efficiency is twice that of B. If A and B working together can complete a task in 6 days, how many days will B alone take?

Accepted Answer

Step 1: Let B's efficiency = x, then A's efficiency = 2x. Step 2: Combined efficiency = 2x + x = 3x = 1/6 (since they complete in 6 days). Step 3: x = 1/18, so B's efficiency = 1/18. Step 4: B alone takes 18 days.

Question 6

The efficiency of P is 25% more than Q. If P and Q together complete a task in 8 days, how many days will P alone take to complete the task?

Accepted Answer

Step 1: Let Q's efficiency = 100%, then P's efficiency = 125%. Step 2: Combined efficiency = 100 + 125 = 225 units. Step 3: Total work = 225 × 8 = 1800 units. Step 4: P's time = 1800 ÷ 125 = 14.4 days.

Question 7

A can complete 40% of a job in 8 days. At this rate, in how many days will A complete the entire job?

Accepted Answer

Step 1: A completes 40% of work in 8 days. Step 2: A's rate = 40/8 = 5% per day. Step 3: To complete 100%, time needed = 100/5 = 20 days.

SSC CHSL Efficiency Problems

Efficiency Problems— Rules & Concept

Key Points to Remember

Exam-Specific Tips

Efficiency Problems — Practice Questions

60-Second Revision — Efficiency Problems