The percentile are converted to your overall rank . This year 869010 students appeared for JEE Main in January .

Therefore, your rank can be calculated using the formula:

(100-your total percentile)X 869010/100

Admission to DTU happens through JAC Delhi counselling. Based on your score/All India Ranks in JEE Main 2020, you have to apply for JAC Delhi 2020 counselling, which will be different from JoSAA counselling 2020.

If your rank is between 40000-50000 , you can gave a great chance of getting admission in DTU for computer science engineering.

National university Singapore and Nanyang Technological university are the among the best universities in Singapore to pursue studies. Both these universities offers various course in the field of engineering.

The degree from both of these universities is world wide acclaimed and acknowledged. Getting admission in these universities is very competitive.
In order to pursue studies in these universities you need to have at least 60% plus marks in 12th.
Apart form academics you also need to take TOEFL or IELTS test.

You can also have look at various cutoff for 2020,2019,2018 on the below link:

https://engineering.careers360.com/articles/jee-main-cutoff

and have a look at various JAC cutoff on the link given below :

https://engineering.careers360.com/articles/jac-delhi

Best of luck