What is the difference between machinery reduced by 20% and machinery reduced to 20%?

In former case machinery value is 80% but in later case machinery value is 20%

The correct answer is option 1- In former case machinery value is 80% but in later case machinery value is 20%. 

The difference between "machinery reduced by 20%" and "machinery reduced to 20%" lies in how the reduction is applied:

In the former case, "machinery reduced by 20%," the machinery's value is decreased by 20% from its original value. So, if the original value of the machinery was 100%, after reducing it by 20%, the machinery's value would be 80%.

In the latter case, "machinery reduced to 20%," the machinery's value is reduced to 20% of its original value. So, regardless of the original value, the machinery's value is now 20%.

Therefore, the correct option is 1 i.e. In former case machinery value is 80% but in later case machinery value is 20%.