Question Detail

A is twice as good as workman as B and together they finish a piece of work in 18 days. In how many days will B alone finish the work.

27 days
54 days
56 days
68 days

Answer: Option B

Explanation:

As per question, A do twice the work as done by B.
So A:B = 2:1
Also (A+B) one day work = 1/18

To get days in which B will finish the work, lets calculate work done by B in 1 day =

$\begin{aligned} =\left(\frac{1}{18}*\frac{1}{3} \right) \\ = \frac{1}{54} \end{aligned}$
[Please note we multiplied by 1/3 as per B share and total of ratio is 1/3]

So B will finish the work in 54 days

1. A tyre has two punctures. The first puncture alone would have made the tyre flat in 9 minutes and the second alone would have done it in 6 minutes. If air leaks out at a constant rate, how long does it take both the punctures together to make it flat ?

$\begin{aligned} 3\frac{1}{5} min \end{aligned}$
$\begin{aligned} 3\frac{2}{5} min \end{aligned}$
$\begin{aligned} 3\frac{3}{5} min \end{aligned}$
$\begin{aligned} 3\frac{4}{5} min \end{aligned}$

Answer: Option C

Explanation:

Do not be confused, Take this question same as that of work done question's. Like work done by 1st puncture in 1 minute and by second in 1 minute.
Lets Solve it:

1 minute work done by both the punctures =

$\begin{aligned} \left(\frac{1}{9}+\frac{1}{6} \right) \\ =\left(\frac{5}{18} \right) \\ \end{aligned}$

So both punctures will make the type flat in

$\begin{aligned} \left(\frac{18}{5} \right)mins \\ = 3\frac{3}{5} mins \end{aligned}$

2. A does half as much work as B in three-fourth of the time. If together they take 18 days to complete the work, how much time shall B take to do it

40 days
35 days
30 days
25 days

Answer: Option C

Explanation:

Suppose B takes x dáys to do the work.
As per question A will take

$\begin{aligned} 2* \frac{3}{4} * x = \frac{3x}{2}days \end{aligned}$

(A+B)s 1 days work= 1/18
1/x + 2/3x = 1/18 or x = 30 days

3. Rahul and Sham together can complete a task in 35 days, but Rahul alone can complete same work in 60 days. Calculate in how many days Sham can complete this work ?

84 days
82 days
76 days
68 days

Answer: Option A

Explanation:

As Rahul and Sham together can finish work in 35 days.
1 days work of Rahul and Sham is 1/35
Rahul can alone complete this work in 60 days,
So, Rahul one day work is 1/60
Clearly, Sham one day work will be = (Rahul and Sham one day work) - (Rahul one day work)

$\begin{aligned} = \frac{1}{35} - \frac{1}{60} \\ = \frac{1}{84} \\ \end{aligned}$

Hence Sham will complete the given work in 84 days.

4. Worker A takes 8 hours to do a job. Worker B takes 10 hours to do a job. How long should it take both A and B, working together to do same job.

$\begin{aligned} \frac{4}{9} \end{aligned}$
$\begin{aligned} 2\frac{4}{9} \end{aligned}$
$\begin{aligned} 3\frac{4}{9} \end{aligned}$
$\begin{aligned} 4\frac{4}{9} \end{aligned}$

Answer: Option D

Explanation:

In this type of questions, first we need to calculate 1 hours work, then their collective work as,

A's 1 hour work is 1/8
B's 1 hour work is 1/10

(A+B)'s 1 hour work = 1/8 + 1/10
= 9/40

So both will finish the work in 40/9 hours
=

$\begin{aligned} 4\frac{4}{9} \end{aligned}$

5. A alone can complete a work in 16 days and B alone can do in 12 days. Starting with A, they work on alternate days. The total work will be completed in

$\begin{aligned} 13\frac{1}{4} \end{aligned}$
$\begin{aligned} 13\frac{1}{2} \end{aligned}$
$\begin{aligned} 13\frac{3}{4} \end{aligned}$
$\begin{aligned} 13\frac{4}{4} \end{aligned}$

Answer: Option C

Explanation:

A's 1 day work = 1/16
B's 1 day work = 1/12

As they are working on alternate day's
So their 2 days work = (1/16)+(1/12)
= 7/48

[here is a small technique, Total work done will be 1, right, then multiply numerator till denominator, as 7*6 = 42, 7*7 = 49, as 7*7 is more than 48, so we will consider 7*6, means 6 pairs ]

Work done in 6 pairs = 6*(7/48) = 7/8

Remaining work = 1-7/8 = 1/8

On 13th day it will A turn,
then remaining work = (1/8)-(1/16) = 1/16

On 14th day it is B turn,

1/12 work done by B in 1 day

1/16 work will be done in (12*1/16) = 3/4 day

So total days =

$\begin{aligned} 13\frac{3}{4} \end{aligned}$

It may be a bit typical question, but if are not getting it in first try then give it a second try. Even not, then comment for explanation for this. We will be happy to help you.

ipsita sarkar 10 years ago

i agree to sankha chakrabarty.procudure-
let work done by b=x
work done by a=2x
(a+b) can do work in 1 day=1/18
atq-1/x+1/2x=1/18
therefore x =1/27 or 27 days
mastguru 11 years ago

Hello Rahim Ji,
You are absolutly right the way you are calculating..
Just a small error , 3/54, you calculated 1/28,
but it will be 1/18, so work will be done in 18 days.
Hope it helps.
ashish 11 years ago

27 is r8 ans

mastguru 11 years ago replied

Hello Ashish, as we are calculating for B, so it answer would be 54, in case we want to calculate for A then answer will be 27.
Mahendran 11 years ago

A is twice good as B so the answer should be divided by 2, then the option A turns green

Question Detail

A is twice as good as workman as B and together they finish a piece of work in 18 days. In how many days will B alone finish the work.

1. A tyre has two punctures. The first puncture alone would have made the tyre flat in 9 minutes and the second alone would have done it in 6 minutes. If air leaks out at a constant rate, how long does it take both the punctures together to make it flat ?

2. A does half as much work as B in three-fourth of the time. If together they take 18 days to complete the work, how much time shall B take to do it

3. Rahul and Sham together can complete a task in 35 days, but Rahul alone can complete same work in 60 days. Calculate in how many days Sham can complete this work ?

4. Worker A takes 8 hours to do a job. Worker B takes 10 hours to do a job. How long should it take both A and B, working together to do same job.

5. A alone can complete a work in 16 days and B alone can do in 12 days. Starting with A, they work on alternate days. The total work will be completed in

Thanks ! Your comment will be approved shortly !

ipsita sarkar 10 years ago

mastguru 11 years ago

ashish 11 years ago

mastguru 11 years ago replied

Mahendran 11 years ago

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Question Detail

A is twice as good as workman as B and together they finish a piece of work in 18 days. In how many days will B alone finish the work.

1. A tyre has two punctures. The first puncture alone would have made the tyre flat in 9 minutes and the second alone would have done it in 6 minutes. If air leaks out at a constant rate, how long does it take both the punctures together to make it flat ?

2. A does half as much work as B in three-fourth of the time. If together they take 18 days to complete the work, how much time shall B take to do it

3. Rahul and Sham together can complete a task in 35 days, but Rahul alone can complete same work in 60 days. Calculate in how many days Sham can complete this work ?

4. Worker A takes 8 hours to do a job. Worker B takes 10 hours to do a job. How long should it take both A and B, working together to do same job.

5. A alone can complete a work in 16 days and B alone can do in 12 days. Starting with A, they work on alternate days. The total work will be completed in

Thanks ! Your comment will be approved shortly !

ipsita sarkar 10 years ago

mastguru 11 years ago

ashish 11 years ago

mastguru 11 years ago replied

Mahendran 11 years ago

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