Aptitude - Time and Work - Discussion

Discussion Forum : Time and Work - General Questions (Q.No. 8)
8.
A can do a certain work in the same time in which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days, then B alone could do it in:
15 days
20 days
25 days
30 days
Answer: Option
Explanation:

(A + B)'s 1 day's work = 1
10

C's 1 day's work = 1
50

(A + B + C)'s 1 day's work = 1 + 1 = 6 = 3 . .... (i)
10 50 50 25

A's 1 day's work = (B + C)'s 1 day's work .... (ii)

From (i) and (ii), we get: 2 x (A's 1 day's work) = 3
25

A's 1 day's work = 3 .
50

B's 1 day's work 1 - 3 = 2 = 1 .
10 50 50 25

So, B alone could do the work in 25 days.

Discussion:
146 comments Page 15 of 15.

Guru said:   2 decades ago
Thank you Nagu i get an idea from your explaination.

Nagu said:   2 decades ago
Hi Guys,

In this problem

A's one day work is equal to (b+c)'s one day work
A = (B+C)

So a+b+c become 2A here they taken instead of b+c= a

so A+B+C = A+ (B+C) = A+A becasue B+C=A
3/25 = 2* (A's one day work)

so 2* A's one day work

I THINK YOU ALL UNDER STOOD THE TRICK..
(1)

Ankit purwar said:   2 decades ago
How u get x= 3/25?

Vinoth said:   2 decades ago
How u got x (A's 1 day's work) = 3/25

Suganya said:   2 decades ago
How you get that 2*(A's 1day work)=3/25

Priyanka said:   2 decades ago
I'm not getting how 2*(a`s 1day work)=3/25


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