Q1.
9 men can do a work in 20 days. How many men are required to complete double of the work in 40 days .
(a) 10 men (b) 6 men (c) 9 men (d) 10 men
Solution.
M1D1W2 = M2D2W1
9 x 20 x 2 = 40 x M2
x 1
M2 = 9
Solution
Q2.
A can do a piece of work in 3 days, B can do it in 4 days and C can do it in 5 days, how long will they take to complete the work.
(a) 1 day (b) 20/19 days (c) 60/47 days (d) 2 days
Solution.
=
3 x 4 x 5 /12 + 15 + 20
=
60 /47
Solution
Q3.
A and B can do a piece of work in 12 days, B and C can do the same work in 15 days, C and A in 20 days. How many days will take it A, B and C
work together.
(a) 20 days (b) 10 days (c) 15 days (d) 18 days
Solution.
2(A + B + C) =
12 x 15 x 20 /180 + 240 + 300
= 5 days
A + B + C = 10 days
Solution
Q4.
A and B can do a piece of work in 30 days and 40 days respectively. They began the work together, but A left the job after some day,
remaining work is finished by B in 12 days. A worked for __________ days .
(a) 9 days (b) 8 days (c) 10 days (d) 12 days
Solution.
Let A worked for x days
(x/30) + (x + 12)/40 = 1
40x + 30x + 360 = 1200
70x = 840
x = 12 days
Solution
Q5.
x men complete a work in 90 days .If 20 men added the work could be finished in 30 less days . find x
(a) 80 men (b) 60 men (c) 40 men (d) 20 men
Solution.
(x) x 90 = (x + 20 ) 60
90x = 60 x + 1200
30x = 1200
x = 40 men
Solution
Q6.
Two pipes A and B can fill a tank in 24 hrs and 32 hrs respectively. If both the pipes are opened simultaneously, after how much time
should B be closed so that the tank is full in 18 minutes ?
(a) 20 minutes (b) 8 minutes (c) 6 minutes
(d) 19 minutes
Solution.
Let pipe B be closed after minutes.
x(1/24 + 1/32) + (18 - x)/24 = 1
x = 8
Solution
Q7.
A man takes 9 hrs to walk from A to B and B to A by riding. He could have gained 3 hrs, if he had covered both way to riding.
How much time he will take to walk both sides.
(a) 6 hrs (b) 8 hrs (c) 12 hrs (d) 10 hrs
Solution.
walking time + riding time = 9 hrs
2 riding time = 6 hrs
one way riding time = 3 hrs
waling time = 9 - 3 = 6
both side waling time = 12 hrs
Solution
Q8.
In 12 hours A man walk from A to B and come back by riding, if he walks both the ways he needs 4 hrs more. How long would he have taken to walk
both sides ?
(a) 25 km (b) 16 km (c) 20 km (d) 30 km
Solution.
(b) 16 km
Solution
Q9.
A man travelled a certain distance by train at the rate of 30 km/hr and walked back 6 km/hr . The whole journey took place 3 hrs.
(a) 10 km (b) 20 km (c) 18 km (d) 15 km
Solution.
= 3 x
30 x 6 /36
=
30 x 6 /12
= 15 km
Solution
Q10.
A train passes two persons who are walking in the direction in which the train is moving . at the rate of 5 m/s and 10 m/s 5 sec
and 6 sec respectively . find the length of the train.
(a) 90 m (b) 120 m (c) 100 m (d) 150 m
Solution.
let x be the speed of train
s1t1 = s2t2
(x - 5) x 5 = (x - 10) x 6
5x - 25 = 6x - 60
-25 + 60 = 6x - 5x
35 = x
length of the train = (35 - 5) 5
= 30 x 5
= 150 m
Solution
