If Rama can do a task in 20 days and Krishna can do it in 30 days, then the time taken by both to complete the task working together is:

Correct option is A

Given:

Rama can complete the task in 20 days.

Krishna can complete the task in 30 days.

Formula Used:

$$T = \frac{1}{\left(\frac{1}{T_1} + \frac{1}{T_2}\right)}$$​​

WhereT₁and T₂ are the individual times taken by Rama and Krishna.

Solution:

Rama's work rate =$$\frac{1}{20} \, \text{task/day}$$​ 

Krishna's work rate = $$\frac{1}{30} \, \text{task/day}$$​

Combined work rate =$$\frac{1}{20} + \frac{1}{30} = \frac{3}{60} + \frac{2}{60} = \frac{5}{60} = \frac{1}{12} \, \text{task/day}$$​

$$T = \frac{1}{\frac{1}{12}} = 12 \, \text{days}$$​

Thus time taken by Rama and Krishna to complete the task together is 12 days.