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:

347 comments Page 18 of 35.

DEEPAK said: 1 decade ago

A = 20, B = 15.

TOTAL WORK FOR ONE DAYS = 7/60.

4 DAYS = 7/15.

Remaining work = 8/15.

Aravind said: 1 decade ago

Why calculate the remaining work (1-7/15) ? The question ask to find the fraction left.

Sri said: 9 years ago

Please give the short trick 'with efficiency' then the sum will be solved very quickly.

Rinkesh said: 1 decade ago

Very simple,
15+20=35
15*20=300
35/300=7/60
work is 1 so=1-7/15
=15-7/15
Ans is = 8/15

Rahul said: 1 decade ago

Can you just guide me to know that how can we calculate the LCM of says 8, 24, 60/7.

Sunita Devi said: 9 years ago

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

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

Sabaneak said: 1 decade ago

If remaining work is 8/15, how many days will it take A alone to complete the work.

Asha Shetty said: 5 years ago

@Mega math.

I can't understand how t simplify 28/60 by 4 and how it becomes 8/15?

MEGA MATH said: 5 years ago

1/15 + 1/20 = 7/60,
7/60*4 = 28/60,
If we simplify 28/60 by 4, then it is 8/15.

Sowmi said: 1 decade ago

Why the value of b had multiplied but in final there is a subtraction is held?

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