Time and Work- Aptitude Questions and Answers

Let A takes X days to complete the work and B takes 2X days
according to question, A takes 30 days less than B, that is X = 2X – 30
X=30

thus ,A take 30 days to complete the work and B takes 60 days
hence, A and B one days work is 1/30 + 1/60 = 1/20

Therefore, the whole job together they will be completed in 20 days

to build a wall of 150*20*12=36000 ,hours required = 16*6*25=2400

to build a wall of 800*15*6=72000 , which is exactly twice as big as the first one,
You need 2400*2 hours = 4800
that is 12*8*days = 4800
days = 4800/96 = 50

One day's work of A and B = (1/10 + 1/20) = 3/20

Work done by A and B together in the 3 days = 3 (1/10 + 1/20) = 9/20
Remaining Work =1- 9/20 = 11/20

1/20 Work done by B in a day
thus,11/20 Work wll be done by B in (11/20)*20 =11 days

3 men can complete work in 30 days
so, Work done by one man in a day = 1/(3*30)
and Work done by one women in a day =1/(4*30))

Thus, 3 men and 6 women will work in a day => 3/(3*30) + 6/(4*30)
= 1/30( 1 + 6/4)
= (1/30)*(10/4) =>1/12

3 men and 6 women do 1/12th part of work in a day,so they will complete the work in 12 days

let A take X days to complete the work and B takes 2X days
according to question, A takes 14 days less than B, that is X = 2X – 14 =>14

thus ,A take 14 days to complete the work and B takes 28 days.

let X persons required to complete the work in 20 days
then, work done => 30 * 24 = X *20

thus ,num of persons, X = 720 / 20 => 36

extra ,more people required = 36 - 30 = 6 persons

let A take X days to complete the work and B takes 2X days.
A's one day work = 1/X , B's one day work = 1/2X
(A+B)'s one day work => 1/X + 1/2X = 1/14
=> 14/X + 14/2X = 1
=> 14+7=X
=> X=21

Thus,
B working alone will require 2*21=42 days to complete the work
A working alone will require 21 days to complete the work

If X can do a piece of work in n days, then X's 1 day's work =1/n

Then (A + B)'s 1 day's work = (1/30 + 1/40) = 7/120
Hence, Time taken by both to finish the work = 120/7 days

If X can do a piece of work in n days, then X's 1 day's work =1/n

B's 9 day's work = 9 * (1/12) = 3/4
Remaining work = (1 - 3/4) = 1/4
1/4 work is done by A in = 20 * (1/4) = 5 day

If X can do a piece of work in n days, then X's 1 day's work =1/n
If A and B, working together,and can complete a piece of work in X days. If A, working alone, can
complete the work in Y days, then B working alone, will complete the work in XY/(Y-X) days.

Then ,B alone can complete = (12 * 8) / (12 - 8) = 96/4 = 24 days

A's 1 day's work = 1/12
B's 1 day's work = 1/12 + 60% of 1/12 = 1/12 x 160/100 = 2/15

Hence,B can do the work in 15/2 days

If A is twice as good a workman as B, then:
(a) Ratio of work done by A and B is 2:1.
(b) Ratio of times taken by by A and B to finish a work is 1:2.

Efficiency (X : Y) = 5 : 1
No. of days (X : Y) = 1 : 5

Work done by 20 persons = 1/3
Remaining work = 1- 1/3 = 2/3
So for double work in same days we need double number of people i.e. 40.

Hence, 20 more people are needed.

6C + 2M = 6 days
36C + 12M = 1 day
As is given 1M = 2C
Then, 36C +12*2C = 1 day
60 children can work in 1 day
Now, 5 men = 10 children
Then, 10 children can work in 6 days.So 5 men also can complete the work in 6 days.

Let a man one day work is X and a boy one day work is Y. Then
6x + 8y =1/10
26x + 48y =1/2
After resolving above equations

x =1/100
y =1/200

15x + 20y = 15/100+20/200 = 1/4
Hence, 15 men and 20 boys to do that work in 4 days

Work done by 6 men = work done by 10 women.
Work done by 1 man = work done by 10 / 6 women= 5/3 women

∴ 12 men + 5 women = 12 x ( 5 / 3) + 5 = 25 women
∴ W1 * D1 = W2 * D2 [W = women, D=days]
10 * 15 = 25 * D2
D2 = 6

A's 1 day's work = 1/15
B's 1 day's work = 1/20
(A + B)'s 1 day's work = 1/15 + 1/20 = (4+3) / 60 = 7/60
(A + B)'s 4 day's work = (7/60) * 4 = 7/15

Therefore, Remaining work = 1 – (7/15) = 8/15