R and S can finish a work in 10 days, S and T can finish it in 12 days and T and R can finish in 8 days. In how many days will the work be finished if they all work simultaneously?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. .
R and S can finish a work in 10 days, S and T can finish it in 12 days and T and R can finish in 8 days
L.C.M(10, 12, and 8) = 120
The efficiency of R and S = 120/10 = 12 units
The efficiency of S and T = 120/12 = 10 units
The efficiency of T and R = 120/8 = 15 units
⇒ 2(R + S + T) = 37
The efficiency of (R + S + T) = 37/2
Now,
The time taken by all three = 120/(37/2) = 120 × 2/37 =