Time and Work - Aptitude Questions and Answers Part 2

Answer: a.	3	Days
	5

Explanation:

In 1 day 3 adults do	1	amount of work ; So, in 1 day, 1 adult does	1/2	=	1	work
	2		3		6

In 1 day, 8 adults do	1	x 8 =	4	amount of work
	6		3

4 boys take thrice the time taken by 3 adults. So, they take 6 days.

In 1 day 4 boys do	1	amount of work; So, in 1 day, 1 boy does	1/6	=	1	work
	6		4		24

In 1 day, 8 boys do	1	x 8 =	1	amount of work
	24		3

In 1 day, 8 adults and 8 boys do	4	+	1	=	5	amount of work
	3		3		3

∴ 8 adults and 8 boys together complete the entire work in	3	days.
	5

Answer: b. 6	2	Days
	3

Explanation:

Tip:
Understanding and solving such problems is very easy by drawing a line.

In 1 day P does	1	work; And in 1 day Q does	1	work
	20		25

As seen above, Q works alone for 10 days.

In 10 days Q completes	1	x 10 =	2	work
	25		5

Remaining work = 1 -	2	=	3	= Done by P and Q together
	5		5

Total Work done = Total days x Work done by all in 1 day
Let P and Q work together for total K days.

∴	3	= K x (	1	+	1	)
	5		20		25

∴ K =	20	= 6	2	days = Days when P and Q worked together
	3		3

Thus P leaves after 6	2	days.
	3

Answer: a. 15 days

Explanation:

Let M and N together finish the work in 'X' days.
So, M when working alone takes 25 days more to complete the entire work.
And, N when working alone takes 1 week and 2 days (i.e.) 9 days more to complete the entire work.

Tip: In such cases, use the following trick -

X = Extra days of P x Extra days of Q

∴ X = 25 x 9 = 15 days = Number of days in which M and N together finish the work

Answer: b.	60	days
	11

Explanation:

A completes the work in 12 days at 8 hour per day = 12 x 8 = 96 hours

In 1 hour, A completes	1	amount of work
	96

B completes the work in 8 days (2 days less than A) working 10 hours everyday (i.e. 2 hours more than A per day) = 8 x 10 = 80 hours

In 1 hour, B completes	1	amount of work
	80

Working together, in 1 hour A and B complete	1	+	1	=	11	amount of work
	96		80		480

So they complete entire work in	480	hours.
	11

Since they work for 8 hours per day, they need	480	x	1	=	60	days
	11		8		11

Answer: d. 13	3	days
	4

Explanation:

This sum is very easy to understand and solve

In 1 day Ram does	1	amount of work
	16

In 1 day Samar does	1	amount of work
	12

First day Ram works and Second day Samar.

So in 2 days, Work done =	1	+	1	=	7	amount of work
	16		12		48

So in 12 days (i.e. 6 times 2days) work done = 6 x	7	=	42	=	7
	48		48		8

Remaining work =	1
	8

Now, on 13th day, Ram will work and complete	1	amount of work
	16

Now, work remaining =	1	-	1	=	1
	8		16		16

We know that in 1 day Samar will complete	1	amount of work
	12

1	>	1
12		16

So, how long would Samar take to finish	1	of work?
	16

=	1	÷	1	=	3
	16		12		4

This means that Samar completes remaining work in 3/4^th day.

So answer is 13 +	3	days = 13	3	days
	4		4