Question

A and B toghether complete a piece of work in 12 days ,B and C can complete it in 20 days and C and A can do it in 15 days .A,B,C toghether can complete it in?
a.10days
b.6days
c.9days
​

Answer 1

Step-by-step explanation:

(A + B)’s 1 day’s work = \frac{1}{12}

(B + C)’s 1 day’s work = \frac{1}{15}

(C + A)’s 1 day’s work = \frac{1}{20}

On adding all above equations,

2(A + B + C)’s 1 day’s work = \frac{1}{12}+\frac{1}{15}+\frac{1}{20}

= \frac{5+4+3}{60} = \frac{1}{5}

∴ (A + B + C)’s 1 day’s work = \frac{1}{10}

∴ B’s 1 day’s work = \frac{1}{10}-\frac{1}{20} = \frac{2-1}{20} = \frac{1}{20}

∴ B alone can do the work in 20 days.

Hence option [A] is correct answer.

Please brainliest please