1. A and B together can complete a
piece of work in 18 days, B and C in 24 days and A and C in 36 days. In how
many days, will all of them together complete the work?
(a) 16 cm
(b) 15 cm
(c) 12 cm
(d) 10 cm
2. A and B can do a piece of work in
72 days, B and C can do it in 120 days, and A and C can do it in 90 days. When
A, B and C work together, how much work is finished by them in 3 days.
(a) 1/40
(b) 1/30
(c) 1/20
(d) 1/10
3. A can complete 2/3 of a work in 4
days and B can complete 3/5 of the work in 6 days. In how many days can both A
and B together complete the work?
(a) 3
(b) 2
(c) 3 ¾
(d) 2 7/8
4. A, B and C can do a piece of work
in 15, 20 and 24 days respectively. If they get R. 76 as the total wages, find
the share of C.
(a) Rs.30
(b) Rs. 40
(c) Rs. 20
(d) Rs. 24
5. A alone can complete a work in 18
days and B alone in 15 days. B alone worked at it for 10 days and then left the
work. In how many more days, will A alone complete the remaining work?
(a) 5
(b) 5 ½
(c) 6
(d) 8
6. A takes twice as much time as B
and thrice as much time as C to finish a piece of work. Working together, they
can finish the work in 2 days. The number of days required by B to do the work
alone is
(a) 4
(b) 6
(c) 8
(d) 12
7. Working efficiency of P and Q for
completing a piece of work are in the ratio 3 : 4. The number of days to be
taken by them to complete the work will be in ratio:
(a) 3 : 2
(b) 2 : 3
(c) 3 : 4
(d) 4 : 3
8. A is 50% as efficient as B, C
does half of the work done by A and B together. If C alone does the work in 20
days, then A, B and C together can do work in
(a) 5 2/3 days
(b) 6 2/3 days
(c) 6 days
(d) 7 days
9. If 10 men or 18 boys can do a
work in 15 days, then the number of days required by 15 men and 33 boys to do
twice the work is
(a) 9
(b) 36
(c) 4 ½
(d) 8
10. If 12 men or 18 women can reap a
field in 14 days, then working at the same rate, 8 men and 16 women can reap
the same field in:
(a) 9 days
(b) 5 days
(c) 7 days
(d) 8 days
Answers and Solution:
1. (a)
Workdone by A and B in 1 day = 1/18
Workdone by B and C in 1 day = 1/24
Workdone by C and A in 1 day = 1/36
so Workdone by 2(A, B and C) in 1 day = 1/18 + 1/24 + 1/36 = 9/72
so Workdone by A, B and C in 1 day = 9/(72*2) = 9/144 = 1/16
so all of them together complete the work in 16 days.
2. (c)
Workdone by (A + B) in 1 day = 1/72
Workdone by (B + C) in 1 day = 1/120
Workdone by (C + A) in 1 day = 1/90
so Workdone by 2(A + B + C) in 1 day = 1/72 + 1/120 + 1/90 = 1/30
so Workdone by (A + B + C) in 1 day = 1/(30*2) = 1/60
so Workdone by (A + B + C) in 3 day = = 1/60 *3 = 1/20
3. (c)
A can complete 2/3 of a work in 4 days
A can complete the whole of a work in (4*3)/2 = 6 days
similarly B can complete the whole of a work in (6*5)/3 = 10 days
so Workdone by A and B in 1 day = 1/6 + 1/10 = 4/15
so Days taken by A and B to complete the whole work = 15/4 = 3(3/4)
4. (c)
Ratio of share of A,B c = ratio of 1 day's work
= 1/15 : 1/20 : 1/24
= 120*1/15:120*1/20 : 120*1/24 = 8:6:5
so sum of ratio turms = 8+6+5 = 19
so The share of C = 76*5/19 = Rs.20
5. (c)
6. (b)
Let B take x day to finish the work.
so A take 2x days and C takes 2x/3 days
so 1/2x + 1/x + 1/(2x/3) = 1/2
so x = 6
so The number of days required by B = 6 days
7. (d)
8. (b)
9. (a)
10 men = 18 boys => 5 men = 9 boys => 15 men = 27 boys
15 men and 33 boys = 27 boys + 33 boys = 60 boys
so 18 boys can do a work in 15 days......I
Let 60 boys can do twice work in x days.....II
so (18*15)/1 = (60*x)/2 => x = 9 days
10. (a)
1. (a)
Workdone by A and B in 1 day = 1/18
Workdone by B and C in 1 day = 1/24
Workdone by C and A in 1 day = 1/36
so Workdone by 2(A, B and C) in 1 day = 1/18 + 1/24 + 1/36 = 9/72
so Workdone by A, B and C in 1 day = 9/(72*2) = 9/144 = 1/16
so all of them together complete the work in 16 days.
2. (c)
Workdone by (A + B) in 1 day = 1/72
Workdone by (B + C) in 1 day = 1/120
Workdone by (C + A) in 1 day = 1/90
so Workdone by 2(A + B + C) in 1 day = 1/72 + 1/120 + 1/90 = 1/30
so Workdone by (A + B + C) in 1 day = 1/(30*2) = 1/60
so Workdone by (A + B + C) in 3 day = = 1/60 *3 = 1/20
3. (c)
A can complete 2/3 of a work in 4 days
A can complete the whole of a work in (4*3)/2 = 6 days
similarly B can complete the whole of a work in (6*5)/3 = 10 days
so Workdone by A and B in 1 day = 1/6 + 1/10 = 4/15
so Days taken by A and B to complete the whole work = 15/4 = 3(3/4)
4. (c)
Ratio of share of A,B c = ratio of 1 day's work
= 1/15 : 1/20 : 1/24
= 120*1/15:120*1/20 : 120*1/24 = 8:6:5
so sum of ratio turms = 8+6+5 = 19
so The share of C = 76*5/19 = Rs.20
5. (c)
6. (b)
Let B take x day to finish the work.
so A take 2x days and C takes 2x/3 days
so 1/2x + 1/x + 1/(2x/3) = 1/2
so x = 6
so The number of days required by B = 6 days
7. (d)
8. (b)
9. (a)
10 men = 18 boys => 5 men = 9 boys => 15 men = 27 boys
15 men and 33 boys = 27 boys + 33 boys = 60 boys
so 18 boys can do a work in 15 days......I
Let 60 boys can do twice work in x days.....II
so (18*15)/1 = (60*x)/2 => x = 9 days
10. (a)
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