Time and Work
Question
Q1.
5 men and 4 boys working together can do three times as much work per day as 2 men and a boy together . compare the work efficiency
of a man and a boy .
Solution.
5m + 4B = 3(2m + B)
5m + 4B = 6m + 3B
- m = - B ⇒ m = B
Solution
Q2.
10 men and 12 women can complete a task in 10 days . In how many days 15 men and 6 women can finish the same task .
solve with Quicker Approch :-
required number of days =
1/
15/10 x 10
+
6/12 x 10
=
=
20/4
= 5 days
Q3.
A and B can do a work in 20 and 25 respectively . They start work together but 6 days . After how many days did A leave ?
Solution.
work completed by B in days =
6/25
work
So A + B together
19/25
work
A + B can do a work in
20 x 25/45
days .
so A + B do
19/25
work in
19/25
x
20 x 25/45
days .
=
76/9
days
Solution
Q4.
x and y can do a work in 12 days , y and z in 15 days , z and x in 20 days . How long x will take seperately to do the same work.
(a) 60 days (b) 30 days (c) 10 days (d) 40 days
Solution.
time taken by x + y + z = 10 days
So,x can do the work in (x + y + z) - (y + z)
=
10 x 15/ 15 - 10
= 30 days
Solution
Q5.
A certain number of men complete work in 50 days. If there were 5 men more, The work could be finished in 5 days less. How many men were
originally there ?
(a) 35 days (b) 40 days (c) 30days (d) 45 days
Solution.
M1D1 = M2D2
(x) x 50 = (x + 5)45
x = 45
Solution
Q6.
9 women or 7 men can do a job in 30 days, how long will 3 women and 6 men take to finish the same job.(Appoximate days)
(a) 19 days (b) 12 days (c) 6 days (d) 18 days
Solution.
(b) 12 days
Solution
Q7.
5 women and 2 boys working together can do four times as much work per day as a women and a boy together . Compare the efficiency of a women with that
of a boy .
(a) 2W = B (b) W = 3B (c) W = 2B (d) W = B
Solution.
(c) W = 2B
Solution
Q8.
A is thrice as fast as B, and is therefore able to finish a work in 60 days less than B. find the time in which they can do it working
together.
(a) 22.5 days (b) 18 days (c) 30.5 days (d) 45 days
Solution.
(a) 22.5 days
Solution
Q9.
8 women and 10 men complete a work in 9 days . Each women take twice the time taken by a man. In how many days will 18 men finish the same
work .
(a) 18 days (b) 11 days (c) 10 days (d) 7 days
Solution.
2 women = 1 man
8 women + 10 men = 14 men
14 x 9 = 18 x (x)
x = 7 days
Solution
Q10.
alone can complete a work in 12 days. A and B together can complete it in 8 days.How long will B alone take to complete the work.
(a)24 days (b)18 days (c)16 days (d)20 days
Solution.
A's 1 day's work = 1/12
(A +B)'s 1 day's work = 1/8
B's 1 day's work
= 1/8 - 1/12
3 - 2/24 = 1/24
B alone can do the work in 24 days.
Solution
