Question

P, Q and R together can build a house in 8 days. P and Q can build the house separately in 20 days and 24 days respectively. In how many days can R build the house alone?​

Answer 1

Answer:

Step-by-step explanation:

30 days

(P + Q)’s 1 day’s work = \frac{1}{12}……….(I)

(Q + R)’s 1 day’s work = \frac{1}{15}…….….(II)

(R + P)’s 1 day’s work = \frac{1}{20}……….(III)

On adding,

2(P + Q + R)’s 1 day’s work = \frac{1}{12}+\frac{1}{15}+\frac{1}{20} = \frac{5+4+3}{60} = \frac{1}{5}

∴ (P + Q + R)’s 1 day’s work = \frac{1}{5\times 2} = \frac{1}{10}……….(IV)

∴ P’s 1 day’s work = \frac{1}{10}-\frac{1}{15} = \frac{3-2}{20} = \frac{1}{30}

∴ P alone will complete the work in 30 days

Answer 2

Answer:

I hope it will help you

P alone will complete the work in 30 days