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- Question
- A can do a piece of work in 24 days, while B can do it in 30 days. With the help of C they can finish the whole work in 12 days.How much time is required for C to complete the work, alone?
Options- A. 100 days
- B. 120 days
- C. 125 days
- D. 72 days
- Correct Answer
- 120 days
ExplanationEfficiency of A = 100/24 = 4.16%
Efficiency of B = 100/30 = 3.33%
Efficiency of (A+ B+C) =100/12 = 8.33%
? Efficiency of C = (8.33) - (4.16 + 3.33) = 0.83%
? Number of days required by C to complete the work alone
= 100/0.83 = 100/(5/6) = 120 days
(Note : 5/6 = 0.833) - 1. A can do a piece of work in 10 days ,B can do it in 15 days. Working together they can finish the work in?
Options- A. 9
- B. 8
- C. 10
- D. 6 Discuss
- 2. you can do a piece of work in 8 days, B can do it in 16,While C can do it in 80 days. In how many days they can complete the whole work, working together?
Options- A. 5
- B. 6
- C. 8 2/3
- D. 20 2/5 Discuss
- 3. 12 men can complete a work within 9 days. After 3 days they started the work, 6 men joined them to replace 2 men. How many days will they take to complete the remaining work?
Options- A. 2
- B. 3
- C. 4
- D. 41/2 Discuss
- 4. 14 men can complete a work in 12 days. 4 days after they started the work, 2 more men joined them. How many days will they take to complete the remaining work?
Options- A. 9 days
- B. 5 days
- C. 6 days
- D. 7 days Discuss
- 5. A can do a certain job in 25 days which B alone can do in 20 days. A started the work and was joined by B after 10 days. The work lasted for?
Options- A. 121/2
- B. 142/9
- C. 15 days
- D. 162/3 Discuss
- 6. A is thrice efficient as B and C is twice as efficient as B. what is the ratio of number of days taken by A,B and C , when they work individually?
Options- A. 2 : 6 : 3
- B. 2 : 3 : 6
- C. 1 : 2 : 3
- D. 3 : 1 : 2 Discuss
- 7. If A takes 4/5 days as B takes and working together they require 20/3 days to complete the whole work. What is the efficiency of B?
Options- A. 62/3%
- B. 16%
- C. 5.55%
- D. 81/3% Discuss
- 8. A is thrice as efficient as B. Working together they complete the work in 3 days. If B take 8 days more then A, What is the number of days taken by A to finish the while work, alone?
Options- A. 4
- B. 2
- C. 12
- D. 16 Discuss
- 9. A and B can do a piece of work in 12 days B and C in 15 days C and A in 20 days. In how many days can C alone do it?
Options- A. 60
- B. 50
- C. 25
- D. 24 Discuss
- 10. A and B can do a piece of work in 8 days, B and C can do the same work in 12 days and A and C complete it in 8 days. In how many days A, B and C can complete the whole work,working together?
Options- A. 4
- B. 6
- C. 12
- D. 9 Discuss
Time and Work problems
Search Results
Correct Answer: 6
Explanation:
Efficiency of A = 10%
Efficiency of B = 6.66%
? Required number of days = 100/16.66 = 6 days
Correct Answer: 5
Explanation:
Efficiency of A = 12.5%
Efficiency of B = 6.25%
Efficiency of C = 1.25%
Efficiency of (A+ B + C) = (12.5 +6.25 + 1.25) = 20%
Required no of days = 100/20 = 5 days
Correct Answer: 41/2
Explanation:
12 men can complete 1/3 of the work in 3 days and the remaining 2/3 of the work in 6 days.
1 man can complete 2/3 of the work in (12 x 6) = 72 days
? (12 - 2 + 6) = 16 men can complete 2/3 of thye work in 72/16 = 41/2 days
Correct Answer: 7 days
Explanation:
? In 12 days work done by 14 men = 1
? In 4 days work done by 14 men = 1 x 4/12 = 1/3
? Remaining work = 1 - 1/3 = 2/3
and number of total men = 14 + 2 = 16
If 1 work is done by 14 men in 12 days
? 2/3 work is done by 16 men in 12 x (14/16) x (2/3) = 7 days
Correct Answer: 162/3
Explanation:
A's 10 day's work = 10 x (1/25) = 2/5
Remaining work = 1 - 2/5 = 3/5
Work was done by (A + B) in 1 day = (1/25 + 1/20) = 9/100
? 3/5 work was done by (A + B) in (100/9 x 3/5) = 20/3 days
Hence, the work lasted for (10 + 62/3) = 162/3 days.
Correct Answer: 2 : 6 : 3
Explanation:
A : B : C
Ratio of efficiency 3 : 1 : 2
Ratio of number of days { 1/3 : 1/1 : 1/2 }
or 2 : 6 : 3
Hence, (a) is correct [ Time = 1/ Efficiency ]
Correct Answer: 62/3%
Explanation:
Efficiency of A + B = 100/(20/3) = 15%
No. of days ( A:B ) = 4 : 5
Efficiency ( A:B ) = 5 : 4
? Efficiency of B = (4/9) x 15 = 20/3 = 62/3%
Correct Answer: 4
Explanation:
Efficiency of A + B = 33.33% = 100/3
Ratio of efficiency of A and B = 3 : 1
? Efficiency of A = (3/4) x 33.33 = 25%
? Number of days taken by A = 100/25 = 4
Correct Answer: 60
Explanation:
Efficiency of (A + B) = 8.33%
Efficiency of (B + C) = 6.66%
Efficiency of (C + A) = 5.00%
? Efficiency of A + B + C = (8.33 + 6.66 + 5) / 2 = 10%
? Efficiency of C = Efficiency of [(A + B + C) - (A + B) ]
= (10 - 8.33) = 1.66%
? No. of days required by C alone = 100/1.66 = 60days
Correct Answer: 6
Explanation:
Efficiency of (A + B) = 12.5%
Efficiency of (B + C) = 8.33%
Efficiency of (C + A) = 12.5%
? Efficiency of [(A + B) + (B + C) + (C + A)] = 33.33%
? Efficiency of (A + B + C) = 16.66%
? No. of days Required by A, B and C together = 100/16.66 = 6 days
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