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- Question
- A and B can do a piece of work separately in 8 and 12 h. If they work alternate hours, A starting, when will the work be finished?
Options- A. 91/2 h
- B. 9 h
- C. 81/2 h
- D. 8 h
- Correct Answer
- 91/2 h
Explanation(A + B +)'s 2 h work = 1/8 + 1/12 = 5/24
(A + B)'s 8 h work = (5 x 8)/(24 x 2) = 5/6
Work done by A in 9th h = 1/8
Total work done upto 9th h = 5/6 + 1/8 = 23/24
Remaining wok = 1/24
B's 1 h work = 1/12
B can do 1/24 of the work = (1/24) x 12 = 1/2 h
So, both can finish the job in 91/2 h. - 1. In a garrison, there was food for 1000 soldiers for one month. After 10 days, 1000 more soldiers joined the garrison. How long would the soldiers be able to carry on with the remaining food?
Options- A. 25 days
- B. 20 days
- C. 15 days
- D. 10 days Discuss
- 2. If 15 men can prepare 12 toys working 5 h per day in 16 days, then in how many days can 10 men prepare 15 toys working 8 h per day?
Options- A. 182/3 days
- B. 183/4 days
- C. 184/5 days
- D. 185/7 days Discuss
- 3. A can do a piece of work in 10 days. B can do it in 24 days. If C also works with them then it take only 6 days to complete the whole work. In how many days C alone can complete the whole work?
Options- A. 25
- B. 40
- C. 50
- D. 75 Discuss
- 4. A piece of work was to be completed in 40 days, a number of men employed upon it did only half the work in 24 days, 16 more men were then set on and the work was completed in the specified time, how many men were employed at first?
Options- A. 16 men
- B. 32 men
- C. 24 men
- D. 48 men Discuss
- 5. If 5 men and 3 boys can reap 23 hectares in 4 days and if 3 men and two boys can reap 7 hectares in 2 days. How many boys must assist 7 men in order that they may reap 45 hectares in 6 days?
Options- A. 2 boys
- B. 6 boys
- C. 4 boys
- D. 5 boys Discuss
- 6. A contractor undertook to do a piece of work in 9 days. He employed a certain number of laborious but 6 of them being absent from the very first day, the rest could finish the work in 15 days. Find the number of men originally employed.
Options- A. 15
- B. 6
- C. 13
- D. 9 Discuss
- 7. Two pipes A and B can each fill a tank in 40 and 60 min, respectively. There is an outlet C. If all the 3 pipes are opened up, the tank will be filled in 30 min. How much time will it take for C alone to empty the full tank?
Options- A. 1 h
- B. 2 h
- C. 3 h
- D. 4 h Discuss
- 8. A conveyer belt delivers baggage at the rate of 3 tonne in 5 min and a second conveyer belt delivers baggage at the rate of 1 tonne in 2 min. How much time will it take to get 33 tonne of baggage using both conveyer belts?
Options- A. 25 min and 30 s
- B. 30 min
- C. 35 min
- D. 40 min and 45 s Discuss
- 9. Rohit, Harsh and Sanjeev are three typists, who working simultaneously, can type 216 pages in four hours . In one hour, Sanjeev can type as many pages more than Harsh as Harsh can type more than Rohit. During a period of five hours, Sanjeev can type as many passages as Rohit can, during seven hours. How many pages does each of them type per hour?
Options- A. 16, 18, 22
- B. 14, 17, 20
- C. 15, 17, 22
- D. 15, 18, 21 Discuss
- 10. A and B together can do a piece of work in 12 days which B and C together can do in 16 days. After A has been working at it for 5 days and B for 7 days, C takes up and finishes it alone in 13 days. In how many days, C alone can do the work?
Options- A. 16 days
- B. 32 days
- C. 24 days
- D. 48 days Discuss
Time and Work problems
Search Results
Correct Answer: 10 days
Explanation:
Let us assume that each soldiers eats one unit of food per day. Thus, total units of food at the beginning will be 1000 x 30 = 30000. After 10 days the 100 soldiers would have eaten 1000 x 10 = 10000 units of food. Thus, food left after 10 days equals 20000 units. Now, there are a total of 2000 soldiers who eat one unit of food everyday.
Now, 30 x 1000 = 1000 x 10 + 2000 x D (here, D is number of days food will last)
? 30000 - 10000 = 2000 x D
? D = 20000/2000 = 10 days
Correct Answer: 183/4 days
Explanation:
Using formula M1D1T1W1 = M2D2T2W2
M1 = 15, M2 = 10, D1 = 16, D2 = ?
T1 = 5, T2 = 8, W1 = 15, W2 = 12
Now, 15 x 16 x 5 x 15 = 10 x D2 x 8 x 12
D2 = (15 x 16 x 5 x 15)/(10 x 8 x 12)
= (15 x 15)/12 = 75/4 = 183/4 days
Correct Answer: 40
Explanation:
Efficiency of A = 100/10 = 10%
Efficiency of B = 100/24 = 4.16%
Efficiency of (A+B+C) = 100/6 = 16.66%
Efficiency of C = (16.66) - (10 + 4.16) = 2.5%
Number of days required by C alone to finish the work = 100/2.5 = 40 days
Correct Answer: 32 men
Explanation:
Let N men were employed at first
? N men do 1/2 of the work in 24 days
? 1 man do the whole work in 24 x 2 x N = 48N days
Now, from the question,
(N + 16) men do the remaining work (1 - 1/2) = 1/2 in (40 - 24) = 16 days
? 1 man do the whole work in 16 x 2 x (N + 16) days
? 48N = 32(N + 16)
? N = 32 men
Correct Answer: 2 boys
Explanation:
5 men + 3 boys can reap 23 hectares in 4 days ......(i)
3 men + 2 boys can reap 7 hectares in 2 days ......(ii)
? From (i),
14( 5 men + 3 boys) can reap 23 x 14 hectares in 4 days
Now, from (ii)
? 23 (3 men + 2 boys) can reap 7 x 2 x 23 hectares in 4 days
? 14(5 men + 3 boys) = 23 (3 men + 2 boys)
? 70 men + 42 boys = 69 men + 46 boys
? 1 men = 4 boys
Now, 5 men + 3 boys = 23 boys
? 23 boys can reap 23 hectare 4 days
? 1 boy can reap 1 hectares in 4 days
? 4 boys can reap 1 hectare in 1 day
? 4 x 45 boys can reap 45 hectaes in 1 day
? 4 x 45 / 6 boys can reap 45 hectares in 6 days
? 30 boys can reap 45 hectares in 6 days
But 30 boys = 28 boys + 2 boys = 7 men + 2 boys
Hence, 2 boys can assist 7 men for the work.
Correct Answer: 15
Explanation:
Let the number of men originally employed = x
So, (x - 6) men could finish the work in 15 days and x men could finish the work in 9 days.
? 9x = 15(x - 6)
? x = 15
Correct Answer: 2 h
Explanation:
Work done by C in one min = (1/40 + 1/60) - 1/30 = 1/120
Hence, C can empty the tank in 120 min or 2 h.
Correct Answer: 30 min
Explanation:
The weight of baggage deliver in 1 min by 1st belt = 3/5 tonne
The weight of baggage deliver in 1 min by 2nd belt = 1/2 tonne
The weight of baggage deliver in 1 min by both belt = 3/5 + 1/2 = 11/10 tonne
So, the two belts delivers 1 tonne in 10/11 min.
Hence, required time to deliver 33 tonne = (10/11) x 33 = 30 min
Correct Answer: 15, 18, 21
Explanation:
Let Rohit, Harsh and Sanjeev can type x, y and z pages respectively in 1 h.
Therefore, they together can type 4(x + y + z) pages in 4 h
? 4(x + y + z) = 216
? x + y + z = 54 .....(i)
Also, z - y = y - x
i.e., 2y = x + z ......(ii)
From Eqs. (i) and (ii), we get
3y = 54
? y = 18
From Eq. (ii), x + z = 36 ....(iv)
From Eqs. (iii) and (iv),
we get x = 15 and z = 21
Correct Answer: 24 days
Explanation:
(A + B)'s one day work = 1/12
(B + C)'s one day work = 1/16
Now, from the question,
A's 5 days work + B's 7 days work + C's 13 days work = 1
? A's 5 days work + B's 5 days work + B's 2 days work + C's 2 days work + C's 11 days work = 1
(A + B)'s 5 days work + (B + C)'s 2 days work + C's 11 days work = 1
? 5/12 + 2/16 + C's 11 days work = 1
? C's 11 days work = 1 - (5/12 + 2/16) = 11/24
? C's 1 day work = (11/24) x 11 = 1/24
Hence, C can do this work in 24 days.
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