A does 80% of a work in 20 days. He then calls in B and they together finish the remaining work in 3 days. How long B alone would take to do the whole work?

23 days
37 days
37½
40 days

Correct Answer: 37½

Explanation:

Whole work is done by A in	❨	20 x	5	❩	= 25 days.
			4

Now,	❨	1 -	4	❩	i.e.,	1	work is done by A and B in 3 days.
			5			5

Whole work will be done by A and B in (3 x 5) = 15 days.

A's 1 day's work =	1	, (A + B)'s 1 day's work =	1	.
	25		15

∴ B's 1 day's work =	❨	1	-	1	❩	=	4	=	2	.
		15		25			150		75

So, B alone would do the work in	75	= 37	1	days.
	2		2

More Questions from Time and Work

A is 30% more efficient than B. How much time will they, working together, take to complete a job which A alone could have done in 23 days?
A and B can together finish a work 30 days. They worked together for 20 days and then B left. After another 20 days, A finished the remaining work. In how many days A alone can finish the work?
A man, on tour travel first 160 km, at 64 km/hr. and the next 160km at 80km/hr. the average speed for the first 320 km. of the tour is?
By walking at 3/4 of his usual speed, a man reaches his office 20 minute later than usual. this usual time is?
A man travels 35 km partly at 4 km/hr and at 5 km/hr. If he covers former distance at 5 km/hr and later distance at 4 km/hr, he could cover 2 km more in the same time. The time taken to cover the whole distance at original rate is
6 men or 10 women can reap a field in 15 days, then the number of days that 12 men and 5 women will take to reap the same field is :
6 children and 2 men complete a certain piece of work in 6 days. Each child takes twice the time taken by a man to finish the work. In how many days will 5 men finish the same work?
2 men or 5 women or 7 boys can finish a work in 469 days, then the number of days taken by 7 men, 5 women and 2 boys to finish the work is :
314 weavers weaves 6594 shawls in 1/6 hours. What is the number of shawls weaved per hour by an average weaver?
The Ratio of efficiencies of A, B and C is 6 : 5 : 4 and if A, B and C received total Rs. 27000 for the whole work. What is the share of C, if the money is distributed in the ratio of amount of work done, individually?

Discussion & Comments

No comments yet. Be the first to comment!