Striving for Jannah

Q: I wanted to ask what is the way that I could get my dua answered 100 percent. I have my o level results in a few days and have prayed since my last exam for a result with nothing below an A and a few A stars InshaAllah! I want this dua really to be fulfiled and I think I had put as much effort as I could during preparation. I request you sir to pray for me and that Allah makes what I want better for me. Please tell me a way to make my dying wish come true.

Dua after Janaazah Salaah

Q:

1. We notice that in some places the Imaam makes dua immediately after the janaazah salaah. Is this correct and among the Sunnah practices of janaazah Salaah?

2. If dua after the janaazah Salaah is not correct, however, for the sake of keeping the peace, can it be done?