1 Answers
Option 2 : Mohan
Given:
Rahul, Mohan and Gagan together complete a task.
Rahul and Mohan together complete 75 percent of the work.
Mohan and Gagan together complete 65 percent of the work.
Concept Used:
Time ∝ 1/Efficiency
Calculation:
Let Rahul, Mohan and Gagan take R days, M days and Q days respectively to complete the Work.
Now, According to the question,
(1/R) + (1/M) + (1/G) = 1 ----(i)
(1/R) + (1/M) = (75/100) ----(ii)
and,
(1/M) + (1/G) = (65/100) ----(iii)
Now, Adding equation (ii) and equation (iii),
(1/R) + 2 × (1/M) + (1/G) = (75/100) + (65/100)
⇒ (1/R) + (2/M) + (1/G) = 140/100 ----(iv)
Now, subtracting equation (i) from equation (iv),
⇒ (2/M) - (1/M) = (140 - 100)/100
⇒ 1/M = 40/100
So, from equation (ii),
1/R = (75/100) - (1/M)
⇒ (75/100) - (40/100)
⇒ 1/R = 35/100
Now, from equation (iii),
1/G = (65/100) - (1/M)
⇒ (65/100) - (40/100)
⇒ 1/G = 25/100
Now, Here 1/M > 1/R > 1/G,
This means Mohan's Efficiency > Rahul's Efficiency > Gagan's Efficiency.
∴ Mohan is the most efficient of the three.
For a given amount of work, the number of persons is inversely proportional to the number of working days, i.e. when the number of person increases then working days decrease and vice - versa.
Working efficiency is the work done by an individual in one day and this efficiency is inversely proportional to the number of days to complete a work.
It means that a person who takes fewer days to complete work is said to be more efficient than a person who takes more days to complete the same work.