Aptitude - Time and Work - Discussion

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

1
4

1
10

7
15

8
15

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 16 of 35.

Shurti said:   7 years ago
@Tabbu.

Here 1 means the whole part.

So subtract the work done from the whole work to get remaining work.

Rohit wadile said:   1 decade ago
(a*b)/a+b = work out.

(15*20)/15+20 = 4.

300/35 = 4.

7/15.

Remaining Work = (1-7/15).

Answer = 8/15.

Niral said:   10 years ago
@Sushmoy.

(1 - 7/15) = 8/15.

Denominator of 1 will be 15 so it will be (15-7/15) = 8/15 will be answer.

Pradosh behera said:   9 years ago
Work is 1part. A and B work is finished 7/15 part in 4days from 1part. Remaining work is 1 - 7/15 = 8/15.

Abhinesh said:   7 years ago
Let,

Do in this way;
Use formula= xy/x+y.
X is 15 and Y 30 if you cross multiply you get an answer.

Vikrant said:   9 years ago
Simple that how get 7/60. 15 + 20/15 * 20 = 35 / 300.
So, 7 * 5 = 35 & 60 * 5 = 300. Thats it!

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.

Akanksha said:   1 decade ago
(1/50+1/20) = (20+15)/300 //This get by cross multiplication.

= 35/300

= 7/60.

How did 300 came?

Latha said:   1 decade ago
Work done=>4*(1/15)+4*(1/20) = 7/15.

Remaining work = 1-7/15.
= 8/15.

Option D.

Surya said:   5 years ago
(1/15+1/20).
Fractions of 15 and 20 are written as;
3*5 and 2'2 *5. = 60,
and 35 go for 7,
= 7/60.


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