P can do as much work in 6 days as Q can do in 7, and Q can do as much work in 8 days as R in 5 days. In what time will R do a piece of work which P can do in 8 days ?
Answer & explanation
Correct answer: option 2
According To Question ,
P × 6 = Q × 7 & Q ×8 = R × 5 ( Total work = Efficiency × Number of days )
Ratio of efficiency P : Q & Q : R
7 : 6 5 : 8
So P : Q : R
7× 5 : 6 × 5
5 × 6 : 8 × 6
Combined ratio 35 : 30 : 48
Total work = Efficiency × Number of days
let R completed same work in d days as done by P in 8 days
P × 8 days work = R × d days work
35 × 8 = 48 × d
d = \(\frac{35}{6}\) = 5\(\frac{5}{6}\) days