1) A and B can complete a piece of work in 8 and 10 days respectively. However, they work alternately, one day each, with A beginning the work. In how much time will the work be completed?
a)8 4/7 days
b)8 2/5 days
c)8 3/5 days
D)8 4/5 days
Click to View Answer
Answer D)8 4/5 days
Work of A and B for first 2 days = 1/8+1/10
= 9/40 of the whole of the work.
Work of A and B for 8 days = 8/2*9/40 of the whole of the work.
Remaining work after 8 days = 1-9/10= 1/10 of the whole of the work.
Since both A and B work alternately one day
each, with A beginning the work. It is the
turn of A for ninth day.
1/8 of the whole of the work is completed by A in 1 day.
so, Remaining 1/10 of the work will be
completed by A in 8/10 = 4/5 days
Hence the required time to complete the work = 8+4/5 = 8 4/5 days .
2)A and B can polish the floors of a building in 25 days. A alone can do 1/3 of this job in 15 days. In how many days can B alone polish the floors of the building?
a)56 1/4 days
b)58 1/4 days
c)56 3/4 days
d)50 1/4 days
Click to View Answer
Answer a)56 1/4 days
It is given that A and B can polish the floors
of the building in 25 days.
Therefore, (A + B)’s 1 day’s work = 1/25
Now, A alone can do 1/3 of the work in 15 days.
so, A alone can do the complete work in
(3 × 15) = 45 days.
or, A’s 1 day’s work = 1/45.
Now, B’s 1 day’s work = (A + B)’s 1 day’s work
– A’s 1 day’s work = 1/25-1/45= 4/225
Hence, B alone can polish the floor in 4/225
days = 56 1/4 days .
3) A can do a piece of work in 10 days and B in 20 days. They work together but 2 days before the completion of the work, A leaves. In how many days was the work completed?
a) 9 days
b) 8 days
c) 10 days
d) 6 days
Click to View Answer
Answer b) 8days
Suppose the work is finished in x days.
then , (x-2)/ 10 + x/20= 1
so, x= 8days .
4)A and B can do a work in 45 and 40 days respectively. They began the work together, but A left after some time and B finished the
remaining work in 23 days. After how many days did A leave?
a) 8 days
b) 10 days
c) 5 days
d) 9 days
Click to View Answer
Answer d) 9 days
A alone can do the work in 45 days.
B alone can do the work in 40 days.
so, A’s 1 day’s work = 1/45
and B’s 1 day’s work = 1/40
(A + B) ’s 1 day’s work = 1/40+1/45= 40+45/ 40*45 .
Let after x days A left the work. Therefore, A
and B together worked for x days.
so, (A + B) ’s x days’ work = 85x /45*40
Again, B works alone for 23 days
so, Work done by B in 23 days = 23/40
Now, according to the question,
85x /45*40+ 23/40 = 1
x= 9 days.
5)10 persons begin to work together on a job but after some days 4 persons leave. As a result, the job which could have been completed in 40 days is completed in 50 days. How many days after the commencement of the work did the 4 persons leave?
a) 30 days
b) 22 days
c) 25 days
d) 35 days
Click to View Answer
Answer c) 25 days
Suppose 4 persons leave after x days. It means
that 10 persons work for x days and (10 – 4 =)
6 persons work for (50 – x) days.
Then 40 days’ work done by 10 persons = x days’
work done by 10 persons + (50 – x) days’ work done by 6 persons.
or, 10 × 40 = 10x + 6(50 – x)
or, 4x = 100
or, x = 25 days.
6)A match box measures 4 cm by 2.5 cm by 1.5 cm. What will be the volume of a packet containing 12 such match boxes? How many such packets can be placed in a card board box whose size is 60 cm × 30 cm × 24 cm?
a) 240
b) 360
c) 580
d) 560
Click to View Answer
Answer a)240
Volume of a match box = (4 × 2.5 × 1.5) cm3 = 15 cm3
= Volume of a packet containing 12 match boxes = (12 × 15) cm3 = 180 cm3.
Now, volume of card board box = (60 × 30 × 24) cm2 = 43200 cm3.
So, Number of packets that can be put in a
card board = 43200/180 = 240.
7)To do a certain work B would take 3times as long as A and C together and C twice as long as A and B together . the 3 men by their united exertions can complete the work in 10 days . how long would each take by himself ?
a)24,40,30,
b)50 ,20 ,60
c)24 , 40, 10,
d)30, 40, 10
Click to View Answer
Answer a) 24,40,30
According to the question , 3times B’s daily work = (A+C)’s daily work
Add B ‘s work both side ,
then ,
4times B’s daily work = (A+B+C)’s daily work = 1/10
B’s daily work = 1/40 …..(1)
also , 2 times C’s daily work =(A+B)’s daily work
add both side C’s daily work,
3times C’s daily work = (A+B+C)’s daily work = 1/10
C’s daily work = 1/30 ……(2)
Now , A’s daily work
= 1/10-(1/40+1/30)= 1/24
A= 24 days , B=40days , C =30 days
Also Check Out Quantitative Aptitude Quiz for IBPS | RRB – Set 265
