Aptitude - Time and Work - Discussion

Discussion Forum : Time and Work - General Questions (Q.No. 1)

Time and Work

A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is :

Answer: Option

Explanation:

A's 1 day's work =	1	;
	15

B's 1 day's work =	1	;
	20

(A + B)'s 1 day's work =		1	+	1		=	7	.
		15		20			60

(A + B)'s 4 day's work =		7	x 4		=	7	.
		60				15

Therefore, Remaining work =		1 -	7		=	8	.
			15			15

Discussion:

344 comments Page 13 of 35.

Dhanalakshmi said: 8 years ago

Thanks for your explanation @Swetha.

Juhi saxena said: 8 years ago

If both 1 day work is 7 then 4 days work is 28 and remaining is 32 how can I change it into fraction? Please explain.

Praveen behera said: 8 years ago

Why (1- 7/15) is applied as 8/15?

Can anybody explain it please?

Prashant Devada said: 8 years ago

@Akash.

You are great, LCM concept makes easy to understand.

Thanks.

Santhosh said: 8 years ago

Can anyone explain this in LCM method?

Ammu said: 8 years ago

A's 1 day work = 1/15.
B's 1 day work = 1/20.

Together for 1 day=(1/15+1/20),
=(4+3)/60,
=7/60.
together for 4 days=(7/60) * 4,
= 7/15.
If total work is 1.
Then the rest is = 1 - 7/15,
= 8/15.

Sunita Devi said: 9 years ago

Why this answer is not sufficient at this term : (7/15)?

Why do this term (1-8/15)?

Ramkali said: 9 years ago

Why do we want to calculate 1-7/15?

Vivek said: 9 years ago

How 7/60 came?

Innareddy chilakala said: 9 years ago

(15 * 20)/15 + 20 = 60/7.
Work done in 4 days (7/60) * 4 = 7/15,
Remaining work is 1 - 7/15 = 8/15.

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