What is 20%,50%,10% of UT,RT,DPT,MPT?

As per my understanding it is fraction/ percentage of inspection of welding to be done, considering whole welding as 100%

Minimum (less than 100%) NDE testing of welds required to assure quality of the product. Minimum NDE percentage is designed for each product e.g. piping class. The persentage might be welder wise or welds wise e.g. if the welder total production is 1000 welds then 100 welds shall undergone NDE assesment either by RT,UT,PT or MT.

Type and Extent  of NDE applicable

This is nothing but the area covered by inspector while carrying out NDT on respective welding joint/surface. Mostly respective standard give idea about percentage of inspection of weld. According to types of joints i.e T joint, butt joints and on partial or full penetration, percentages depends. Also it is important to know that, whatever the joints or percentages given, VT (Visual test) & DT (Dimensional Test) of weld are always 100%. 

i think that all the ndt as per customer requirement.

that is percentage of joints to be inspected in a project ie; in piping or in tanks etc.

20% UT , 50% RT AND 10% PT&MT

This is percentage of Inspection of welding,The persentage might be welder wise or welds wise.

i have got 75 in this traning 

These are percentage of application of NDT. Ex. RT for a hundred welds requires 20% of test as standard practice.

It is the percentage of area covered  by inspector