Question Detail

A is thrice as good a workman as B and takes 10 days less to do a piece of work than B takes. B alone can do the whole work in

15 days
10 days
9 days
8 days

Answer: Option A

Explanation:

Ratio of times taken by A and B = 1:3
Means B will take 3 times which A will do in 1 time

If difference of time is 2 days, B takes 3 days
If difference of time is 10 days, B takes (3/2) * 10 =15 days

1. A can do a piece of work in 4 hours . A and C together can do it in just 2 hours, while B and C together need 3 hours to finish the same work. In how many hours B can complete the work ?

10 hours
12 hours
16 hours
18 hours

Answer: Option B

Explanation:

Work done by A in 1 hour = 1/4

Work done by B and C in 1 hour = 1/3

Work done by A and C in 1 hour = 1/2

Work done by A,B and C in 1 hour = (1/4)+(1/3) = 7/12

Work done by B in 1 hour = (7/12)–(1/2) = 1/12

=> B alone can complete the work in 12 hour

2. A can do a job in 16 days, B can do same job in 12 days. With the help of C they did the job in 4 days. C alone can do the same job in how many days ?

$\begin{aligned} 6\frac{1}{2}days \end{aligned}$
$\begin{aligned} 7\frac{1}{2}days \end{aligned}$
$\begin{aligned} 8\frac{3}{5}days \end{aligned}$
$\begin{aligned} 9\frac{3}{5}days \end{aligned}$

Answer: Option D

Explanation:

In this question we having, A's work, B's work and A+B+C work. We need to calculate C's work.
We can do it by,
(A+B+C)'s work - (A's work + B's work).

Let's solve it now:

C's 1 day work =

$\begin{aligned} \frac{1}{4}- \left(\frac{1}{16} +\frac{1}{12} \right) \\ =\left(\frac{1}{4} - \frac{7}{48} \right) \\ = \frac{5}{48} \end{aligned}$

So C can alone finish the job in 48/5 days,
Which is =

$\begin{aligned} 9\frac{3}{5}days \end{aligned}$

3. 10 women can complete a work in 7 days and 10 children take 14 days to complete the work. How many days will 5 women and 10 children take to complete the work?

6 days
7 days
8 days
9 days

Answer: Option B

Explanation:

1 woman's 1 day's work = 1/70
1 Child's 1 day's work = 1/140
5 Women and 10 children 1 day work =

$\begin{aligned} \left(\frac{5}{70}+\frac{10}{140}\right) \\ = \frac{1}{7} \end{aligned}$

So 5 women and 10 children will finish the work in 7 days.

4. A can do a certain job in 25 days which B alone can do in 20 days. A started the work and was joined by B after 10 days. The number of days taken in completing the wotk were ?

$\begin{aligned} 14\frac{2}{3}kmph \end{aligned}$
$\begin{aligned} 15\frac{2}{3}kmph \end{aligned}$
$\begin{aligned} 16\frac{2}{3}kmph \end{aligned}$
$\begin{aligned} 17\frac{2}{3}kmph \end{aligned}$

Answer: Option C

Explanation:

Work done by A in l0 days = (1/25) *10 = 2/5
Remaining work = 1 - (2/5) = 3/5
(A+B)s 1 days work = (1/25) + (1/20) = 9/100

9/100 work is done by them in 1 day.
hence 3/5 work will be done by them in (3/5)*(100/9)
= 20/3days.

Total time taken = (10 + 20/3) = 16*(2/3) days

5. A can finish a work in 18 days and B can do same work in half the time taken by A. then working together, what part of same work they can finish in a day

Answer: Option B

Explanation:

Please note in this question, we need to answer part of work for a day rather than complete work. It was worth mentioning here because many do mistake at this point in hurry to solve the question

So lets solve now,
A's 1 day work = 1/18
B's 1 day work = 1/9 [because B take half time than A]

(A+B)'s one day work =

$\begin{aligned} \left(\frac{1}{18}+\frac{1}{9} \right) \\ =\left(\frac{1+2}{18} \right) \\ = \frac{1}{6} \end{aligned}$

So in one day 1/6 work will be done.

sindhu 9 years ago

could anyone explain 5th question more clearly
Anirban Majumder 10 years ago

{K/(K-1)}* LESS DAYS
{3/(3-1)*10}
(3/2)*10
3*5
15DAYS
Anirban Majumder 10 years ago

short cut :-
times less/ (K-1) where K is efficiency
therefore 10/ (3-1)
=5 hence A takes 5 days to do the work {& which is 10 days less than that of B}
so B takes 10+5 = 15 days
manasa 11 years ago

could you please explain this prob.

mastguru 11 years ago replied

Hello Manasa,
In this type question where working capacity is given and we need to calculate the time.
If you do certain work faster than me, then you will take less time than me, right !
Now A is three times better workman than B.
So, the work which B will do in 3 days, A will do in 1 day.
So Ratio of time is 1:3
If difference of time is 2 days, B takes 3 days (Please note from ratio 3 - 1 = 2)
If difference of time is 10 days, B takes (3/2) * 10 =15 days.
Thanks

Question Detail

A is thrice as good a workman as B and takes 10 days less to do a piece of work than B takes. B alone can do the whole work in

1. A can do a piece of work in 4 hours . A and C together can do it in just 2 hours, while B and C together need 3 hours to finish the same work. In how many hours B can complete the work ?

2. A can do a job in 16 days, B can do same job in 12 days. With the help of C they did the job in 4 days. C alone can do the same job in how many days ?

3. 10 women can complete a work in 7 days and 10 children take 14 days to complete the work. How many days will 5 women and 10 children take to complete the work?

4. A can do a certain job in 25 days which B alone can do in 20 days. A started the work and was joined by B after 10 days. The number of days taken in completing the wotk were ?

5. A can finish a work in 18 days and B can do same work in half the time taken by A. then working together, what part of same work they can finish in a day

Thanks ! Your comment will be approved shortly !

sindhu 9 years ago

Anirban Majumder 10 years ago

Anirban Majumder 10 years ago

manasa 11 years ago

mastguru 11 years ago replied

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Question Detail

A is thrice as good a workman as B and takes 10 days less to do a piece of work than B takes. B alone can do the whole work in

1. A can do a piece of work in 4 hours . A and C together can do it in just 2 hours, while B and C together need 3 hours to finish the same work. In how many hours B can complete the work ?

2. A can do a job in 16 days, B can do same job in 12 days. With the help of C they did the job in 4 days. C alone can do the same job in how many days ?

3. 10 women can complete a work in 7 days and 10 children take 14 days to complete the work. How many days will 5 women and 10 children take to complete the work?

4. A can do a certain job in 25 days which B alone can do in 20 days. A started the work and was joined by B after 10 days. The number of days taken in completing the wotk were ?

5. A can finish a work in 18 days and B can do same work in half the time taken by A. then working together, what part of same work they can finish in a day

Thanks ! Your comment will be approved shortly !

sindhu 9 years ago

Anirban Majumder 10 years ago

Anirban Majumder 10 years ago

manasa 11 years ago

mastguru 11 years ago replied

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