Aptitude - Time and Work - Discussion

A = B+C( A work is equal to B and C work)---> 1
A+ B = 10 days (A and B can do a work in 10 days)--> 2
C=50 days( C alone do work in 50 days)----> 3.

Let's assume work as a 50 parts.(take LCM of 10,50).

A+B=5parts(A anb B can do 5 parts a day work)--> 4.
C=1 part(C can do work 1 part a day I,e 50 parts 50 days)---> 5.

From equation 1: A=B+C
A = B + 1(from eq 5).
3 + 2 = 5(from eq 4).
B = 2 parts.
50 parts of work can do in 25 days. B can do parts a day.

Thanks @Sneha.

You explained it well.

This problem we can do it in a simple way.

(A+B)'s 1 day's work = 1/10;
C's 1 day's work = 1/50;
A's 1day's work = (B+C)'s 1day's work;
i.e. A+B = 1/10;

(B+C)+B = 1/10;
2B+C = 1/10;
2B = (1/10) - (1/50);
2B = 4/50;
B = 2/50;
B = 1/25;

So, B alone can do it in 25 days.

How come 1/10, Can you please explain it?

Thank you @Awoke your method was so easy.

A=B+C --- (1).
A+B=1/10 --- (2).
C=1/50 --- (3).

Substitute C in eq 1.
A=B+ (1/50).
From eq 2 we get A= (1/10) -B.
Substitute this in above eq.

(1/10)-B=B+ (1/50).

Solve it.

Thank you @Sneha you made the given solution easier to understand.

Thank you @Awoke your method was easy.

A = b+c.

A+b = 1/10,c=1/50
B+C+B = 1/10.

2b = (1/10)-(1/50).
2b = 2/25,
b = 1/25,
So,b = 25.

We know A+B= 10 ----> 1
C=10 ----> 2
GIVEN;
A=B+C ----> 3.

JUST PUT 3, 2 IN 1
B + C + B = 10
2B + 60 = 10
B = -50/2
B = 25 (IT BECAME POSITIVE BECAUSE DAY IS NOT In NEGATIVE).