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.

5 views

Related Questions