Amar can do a work in 15, and Ravi can do in 25 days and Samar in 30 days. How long they will take to do the work if they work together ?
a)11/2 days | b)13/2 days |
c)50/7 days | d)20 days |
Amount of work done by Amar = 1/15
Amount of work done by Ravi = 1/25
Amount of work done by Samar = 1/30
Total amount of work done by all = 1/15 + 1/25 + 1/30 = (10 + 6 + 5)/150 = 21/150 = 7/50
thus All take 50/7 days to finish the work
Rajat alone does a piece of work in 2 days and Rajesh does it in 6 days. In how many days will the two the two do it together ?
a)3/2 days | b)4 days |
c)2 days | d)3 days |
Amount of work done by Rajat = 1/2
Amount of work done by Rajesh = 1/6
Total amount of work done by both = 1/2 + 1/6 = 2/3
Therefore both will take 3/2 days
A can do a piece of work in 24 days. If B is 60% more efficient than A, then B can complete work in :
a)17 days | b)18 days |
c)15 days | d)12 days |
A's one day's work = 1/24
Therefore, B's one day's work = 160% of 1/24
= 160/100 * 1/24 = 1/15
Therefore, B will take 15 days to finish the work.
A, B and C working together take 30 min to address a pile of envelopes. A and B together take 40 min, A and C together take 45 min. how long would each take working alone ?
a)A : 72 min, B : 90 min, C : 120 min | b)A : 42 min, B : 90 min, C : 120 min |
c)A : 72 min, B : 90 min, C : 100 min | d)A : 72 min, B : 80 min, C : 120 min |
Here 1/A + 1/B + 1/C = 1/30 ... (i)
1/A + 1/B = 1/40 .... (ii)
and 1/A + 1/C = 1/45 .... (iii)
From (i) and (ii)
1/C = 1/30 - 1/40 = 1/120
1/A = 1/45 - 1/C = 1/45 - 1/120 = 1/72
1/B = 1/40 - 1/A = 1/40 - 1/72 = 1/90
So A alone will address in 72 min, B alone will address in 90 min, and C alone will address in 120 min.
24 men completes a given job in 40 days. The number of men required to complete the job in 32 days is :
a)32 men | b)30 men |
c)35 men | d)36 men |
Here indirect proportion so less days, more men
Let the number of required men to complete the work be x
Therefore, 32 : 40 : : 24 : x
32/40 = 24/x
=> x = (24 x 40)/32 = 30
If the work done by (x – 1)men in (x + 1) days is to the work done by (x + 2) men in (x – 1) days are in ratio 9 : 10, then x is equal to :
a)5 | b)6 |
c)8 | d)7 |
Let the work by (x - 1) men in (x + 1) day = 9z
Then work done by 1 man in one day = [9z/(x - 1) * 1/(x + 1)]
Let the work done by (x + 2) men in (x - 1) days = 10z,
Therefore, Work done by 1 man in 1 day = [10z/(x + 2)(x - 1)]
Therefore, [9z/(x - 1)(x + 1)] = [10z/(x + 2)(x - 1)]
=> 9(x + 2) = 10(x + 1)
=> x = 8
a)20 hours | b)60 hours |
c)45 hours | d)46 hours |
A group of workers engaged in plastering a wall completed ½ of the work in one day and ¼ of the remaining work the next day. If still 45 square metre of wall remained to be plastered. What was the area of the wall ?
a)300 sq. metre | b)120 sq. metre |
c)240 sq. metre | d)180 sq. metre |
Let 'a' be the area to be plastered.
Here the work completed on the first day = x/2 m2
The work completed on the second day = 1/4 * x/2 = x/8
Therefore, x - x/2 - x/8 = 45
Therefore x = 120 m2
Rani and Sneh working separately can finish a job in 8 and 12 hours respectively. If they work for an hour alternately, Rani beginning at 9.00 a.m. When will the job be finished ?
a)7 : 30 p.m. | b)7 : 00 p.m. |
c)6 : 30 p.m. | d)6 : 00 p.m. |
Capacity of Rani and Snehper hour = 1/8 and 1/12 respectively.
Total work done by them in 1 hour = 1/8 + 1/12 = 5/24 per hour
Therefore, full work = 1 x 48/5 = 9hours then left 1/6 of work and now its Sneh turn. Sneh will do the remaining work in 30 min.
Total time taken = 9 hour 30 min
time = 9 am + 9 hour 30 min = 18.30 hour
= 6.30 pm
2 men undertake to do a job for Rs. 1400. One can do it alone in 7 days and the other 8 days. With the assistance of a boy they finish the work in 3 days. How should the money be divided ?
a)Rs. 600, Rs. 525, Rs. 275 | b)Rs. 550, Rs. 500, Rs. 350 |
c)Rs. 650, Rs. 470, Rs. 280 | d)None of the above |
Let the boy completes the work in x days, thus according to the condition
1/7 + 1/8 + 1/x = 1/3
or 1/x = 1/3 - 1/7 - 1/8 = 11/168
so x = 168/11 days
So money is to shared in the ratio
1/7 : 1/8 : 11/168 or 24 : 21 : 11
Thus A's amount = 24/56 x 1400 = Rs. 600
B's amount = 21/56 x 1400 = Rs. 525
Boy's amount = 11/56 x 1400 = Rs. 275
An amount is sufficient to pay A’s wages for 21 days and B’s wages for 28 days. The amount is sufficient to pay wages to both for :
a)22 days | b)26 days |
c)24.5 days | d)12 days |
Let the total amount be x
Here A's one day's wage = x/21
B's one day's wage = x/28
therefore, A's and B's wages = x/21 + x/28 = x/12
Therefore, the amount is sufficient to pay 12 days wages to both
Two pipes A and B can separately fill a tank in 12 minutes and 15 minutes respectively. Both the pipes are opened together. But 4 minutes after the start pipe A is turned of. How much time it will take to fill the tank ?
a)11 minute | b)6 minute |
c)12 minute | d)8 minute |
Part of tank filled by A in a minute = 1/12
Part of tank filled by B in a minute = 1/15
Therefore, total part filled in a minute = 1/12 + 1/15 = 3/20
Therefore, part filled in 4 minutes = (4 x 3)/20 = 3/5
Now remaining part = 1 - 3/5 = 2/5
Therefore, greater part, more time
1/15 : 2/5 : : 1 : x
=> x/15 = 2/5
=> x = 6 min
If 10 persons can do a job in 20 days. Then 20 persons with the twice efficiency can do the same job in :
a)10 days | b)20 days |
c)5 days | d)15 days |
Let the number of days be x.
Here efficiency is 2 : 1
Person 20 : 10
Number of days 20 : x
therefore, x = (1 x 10 x 20)/(20 x 2) = 5 days
9 men finish one third work in 10 days. The number of additional men required for finishing the remaining work in 2 more days will be :
a)78 | b)81 |
c)55 | d)30 |
Time taken by 9 men to finish the job = 30 days
Remaining job = 1 - 1/3 = 2/3
More work left so more men required (direct proportion)
[less days, more men (indirect proportion)]
Work 1/3 : 2/3y : : 9 : x
Days 2 : 10
Therefore, x = 2/3 x 10 x 9 x 3 x 1/2 = 90 men
Thus required men = 90 - 9 = 81
a)17(1/2) minute | b)23(2/7) minute |
c)20 minute | d)15 minute |
NGO the Harmony Foundation honored former Miss Universe Sushmita Sen with the Mother Teresa Memorial International Award...
Read moreNew York City Mayor Michael R. Bloomberg has been selected for the inaugural Genesis Prize – an award popularly dubbed...
Read more