15 men can complete a task in 30 days. In how many days can 20 men complete that task?

Correct option is D

Given:

$$15 \, \text{men} = 30 \, \text{days}$$​​

Formula Used:

$$\text{Work} = \text{Men} \times \text{Days} \, (\text{constant})$$​​

Solution:

$$15 \times 30 = 20 \times \text{Days}$$​

​$$\text{Days} = \frac{15 \times 30}{20} = 22.5 \, \text{days}$$ 

Thus, 20 men complete the work in 22.5 days